yup well i took ur advice and got mercury to do it today.
As luck would have it the Redline BOV i purchased doesn't dump to atmosphere in 1 great fucken wiss. It's a variable valve release which seems to overcome at least some of the problem of backfires. After a couple of adjustments and a few rather loud explosions coming from the bottom of the car later and we seem to have found a sweet spot.
Boost next!!
thanks for all your help folks.