They are Lycoming, I think 0360, I should know really I fly them! We had another G-BDCC ex Boscombe but that got w/o about 10 years ago. Also still at Hus Bos is my old a/c WP809 (G-BVTX) which retains the RN colours, that was never converted. The reason for the bigger engine is they are used as glider tugs.