[Lynn Eades]

Petr, I concur with Ben. Your carrier is as you say, quite a lot later than mine (built in 41) The lack of square holes in the rear hull plate means that aill the hot air exits through the mesh screen at the top rear of the engine cover.
The big round hole is the hull drain hole. It has a long rod up to the top, and is unwound to open from inside the mesh screen. If I recall there is a picture of it in the drawing folder of Nigels third book.
This is a rare carrier.