Fitting a Gasket Trim

Muso101

Morning

Decided to replace the gasket plastic external trim on my Pegasus 534,wish I hadn't!!  It's driving me mad...any suggestions as to how fit one of these?   I think probably the only way is to cut it into sections?  but I would have liked to have replaced it with just one piece,but I think this is probably impossible??

Enjoy the weather

Muso