After doing a bit of reading online, I have decided on ordering a new pcv. The pcv I have was working as far as i know. (as was new)
But after some reading, I saw some recommendations saying you should buy a pcv that is correctly calibrated for the type and size of engine you're using. For the avoidance of doubt I have ordered a Chevrolet/GM pcv for a sbc350 to fit.

I plan to install that plus the closed grommet with some drilled holes (that v8muscle recommended), top up my oil and see how I get on over the next few weeks.

Cheers for the advice everyone

Fingers crossed,