2003 Mazda RX8 Engine starting problems when hot

Engine Mechanical problem
2003 Mazda RX8 Two Wheel Drive Manual

I have a 2003 RX-8 231bhp which has had starting problems since I bought it which are worsening. It has had new plugs and starter motor (spins faster) fitted by a main dealer who has now given up with it. The problem is that the engine starts fine when cold as the auto-choke kicks in. When the engine is fully warmed up though it can take 30 minutes of cool down before starting again. Before the main dealer gave up with it he did say the compression was a bit low but that they had submitted that to Mazda technic and they did not think it was a problem. Need to know if it is worth taking this to another dealer? If not then a recommended workshop in the UK north west. If the problem is compression then what options are available?