I have a few new bits to go on the car, vapour blasted inlet manifold, plenum and throttle body. What gains would be had from porting any or all of them? I am currently running stage 2 at just under 300bhp (hybrid, fmic and flea map + a few other goodies).

no benefit worth noting by porting on the inlet side (other than the head, of course) - the only modification worth it at this level is matching the exhaust manifold to the gasket to remove the large step down in size

Nigel you beat me to it

on another note though if you have the parts sitting around you might aswell port and polish everything now so you dont have to do it when your bitten by the power bug later

Yep, the parts are sitting around waiting to be fitted so no hurry. I'm not planning on going much further with the power (i'm pretty sure everyone has said that before) and Barbz has already ported the exhaust manifold. If it isn't going to do any harm and won't cost the earth i might just get it done. There are more important things due for the new year however so it will be on the bottom of the list.
Cheers for the advice.