You are wrong here.
The Royal Navy by June 1944 is currently conducting Naval Bombardments and Air raids against Japanese occupied Indonesia, however the India situation will lead to a shift in priorities...
So you must of forgotten of the
Eastern Fleet based in the port of Trincomalee, Ceylon (Sri Lanka). The Royal Navy as of June 1944 currently has the...
3rd Battle Squadron,
5th Cruiser Squadron,
4th Destroyer Flotilla,
7th Destroyer Flotilla,
11th Destroyer Flotilla,
4th Submarine Flotilla,
6th Submarine Flotilla.
Also this Wikipedia page has
ALL the major ships in the Eastern Fleet listed.
I'm going to list out what I could find from that Wikipedia page.
The Royal Navy and French Navy by June 1944 will have the Battleships MN Richelieu (leaves for repairs by September), HMS Queen Elizabeth and HMS Valiant (leaves after taking severe accidental damage in August).
The Battlecruiser HMS Renown is in the Indian Ocean Fleet.
The second last Battleship to ever be built for the Royal Navy, HMS Howe will be crossing the Suez Canal in July and will arrive by August, 1944.
The 3rd Battle Squadron will always have 2 Battleships and 1 Battlecruiser at all times until 1945 at least.
As for Fleet Carriers of the Royal Navy by the end of June will be made up of HMS Illustrious and the support Carrier HMS Unicorn.
Fleet Carriers HMS Indomitable and HMS Victorious will arrive by July.
So the Royal Navy will have 3 operational Fleet Aircraft Carriers by July and 1 Support Carrier.
Escort Carriers HMS Ameer, HMS Atheling, HMS Battler, HMS Begum, and HMS Shah are operating in the Indian Ocean at this time.
The 5 Escort Carriers are usually used to escort and protect Allied Convoys and also transport Aircraft across the seas, but with India in crisis most of them will be moved over to support the British Army.
As for Heavy Cruisers the Royal Navy had in June there was HMS Cumberland, HMS London, HMS Suffolk and lastly HMS Sussex. They were all part of the 5th Cruiser Squadron.
The 4 Heavy Cruisers are all part of the 5th Cruiser Squadron.
Light Cruisers were noted with 9 of them available by June. Some of them are Australia, New Zealander and Dutch. It is known that...
5 of them are Modern ships.
3 of them are older ships.
1 of them is obsolete.
Now I think the Allies have somewhere around 14 or more Destroyers operating around the Indian Ocean by June, 1944. Most of them are part of the Destroyer Flotilla's in Trincomalee, the rest are being used for Convoy Defense I believe a lot of Australians ships are noted.
The Royal Navy has I think roughly 9 River-class Frigates for Anti-Submarine purposes mainly, but the ships can be used for Coastal Bombardments.
The Royal Navy Sloop fleet is mostly made up of insignificant former US Coast Guard boats, but their is 1 British Black Swan-Class ship operating in the Indian Ocean, the "Royal" Indian Navy has 6 of them however.
Lastly there is roughly around 16 British and Dutch Submarines in the Indian Ocean by June, 1944.
Everything else is mostly miscellaneous.
So to summarise, the Allies will likely have...
2 Battleships
1 Battlecruiser
3 Aircraft Carriers
1 Light Carrier
5 Escort Carriers
4 Heavy Cruisers
9 Light Cruisers
14 Destroyers
9 Frigates
1 Sloop
16 Submarines
Well I expect for the blueprints of the mass produced Type C and D-class of
Kaibōkan ships to be delivered along with the construction of Japanese MTB's and Coastal boats getting armed with weapons.
Japanese Daihatsu-class landing boats will be built to help transport the IJA across the rivers of India and the coast.
Now the main issue with building the Kaibōkan ships will be finding the engines that are compatible with the designs of the ship will be difficult and delay the construction of the Indian Navy, ships obviously can't be controlled if you have no engines to power them.
Getting the Naval guns will also be a issue as well but their should be plenty of leftover British Artillery pieces across the Subcontinent that can be used instead.
There should be enough Industrial power in India to turn the nation into a formidable force to be reckoned with.
Provided that it isn't destroyed by the British Bombers of
Tiger Force...
Well Churchill could order for more reinforcements from the Commonwealth Nations into Sri Lanka and the Maldives.
Their is nothing stopping the Royal Navy Battleships from opening fire on rebels in the Islands and causing devastation, however this will mean that British power will only remain in the Coastal and developed areas of Ceylon.
If the Japanese do land the 'Lanka Regiment' of the INA into Ceylon with the use of Submarines then I don't see how the British will hold onto the Island for long without resorting to extreme measures.
The threat of Axis Airplanes and Ships alongside with Submarines will or should eventually force the British to start a Dunkirk style operation to save what's left of their military in the islands.
But Churchill is going to adamantly refuse to abandon the islands and will retaliate with Strategic and tactical bombing against the islands with the planes from the Aircraft Carriers and RAF Wellington bombers. But it won't be useful in the forest and hills of Sri Lanka.
The only real hope left for Britain is for American support and help with crushing the resistance in the Islands and allowing the British to strategically Bomb the Indian Subcontinent into submission with the help of Tiger Force.
The Bombing campaign is not going to save British India, but it will kill hundeds of thousands of lives. And will only leave bitter resentment and hatred from the peoples of India.
Britain will definitely give up and abandon ship after Churchill loses the British election in July, 1945 but that's a whole year for Bose to struggle through.
The only thing left standing in the way of India in the aftermath will be the steamroller that is the United States of Ameria and the juggernaut that is the Union of Soviet Socialist Republics...