thing
My mate's dad flew Sunderlands out of Koggala, I think you're probably the only other person that's heard of it!
As someone who served at China Bay and Negombo (Katunayake) I know of it!
FWIW a bit of China Bay WWII history.
On 10-11th August 1944 31 USAAF B.29's flew from China Bay against the Palembang oil refineries in Japanese occupied Sumatra - the 3,900 miles flight from Ceylon to Palembang and back was the longest single-stage flight undertaken by USAAF combat aircraft in WWII. Only one aircraft was lost when it ran out of fuel.
Also long-range RAF B.24 Liberators and Catalinas flew supply and agent dropping missions from China Bay in support of SOE operations in Burma and Malaya.