ive got a smoking issue i cant seem to sort out,
car is a rs1600i with a TT kit dosent do many miles hence the long time period of faults


all was good up to about 2 years ago when the turbo shat itself, filled the exhaust with oil etc,
turbo was sent to TT for a rebuild, on refitting there was a lot of blue smoke, I expected some due to exhaust etc but it was fine while driving but when stationary the car practically disappeared in clouds of it, I suspected bottom end damage as it was untouched for over 30 yrs, upon stripping all looked ok apart from a crack in the block, this was declared as no use so a replacement block was sourced, this was bored out to take the +1mm pistons and was built up with new rings, mains big ends etc, I also used a different head when I put it back in the car, drove spot on but again still smoked when idling like in a traffic queue but not as bad as initially, its since had a new exhaust back box (single box system) and has covered about 600 miles.
a few days ago I thought perhaps it was a defect in the head so I have now refitted the original head, valves were lapped in to get a perfect seal and of course new stem seals fitted, up and running now but still smoking,
on initial cold start all is fine its after about 2-3 mins of idling it starts, appears to be mainly blue smoke, not loosing water and lambda is showing 13.8 on the afr gauge, I assume that this is down to not being burnt off until the exhaust temp is up~?
oil pressure shows about 5 bar on cold start dropping to 2ish when warm. if I rev the engine the smoke will clear after a few seconds and then return again after idling from about a minute,
all breather hoses are new and clear,
is it likely to be the turbo? no play in the shaft and spins freely

when driving no smoke is visable on boost or when backing off

did a comp test yesterday and got about 110bar on all 4 (cheap ebay tester not convinced its accurate)
any suggestions welcomed,

cheers