What do you think?
The reasons were cost, coupled with a choked Air filter which gave extreme
pressure imbalance across the turbo.
This caused oil to bypass the Turbo seals in heavy rain on the M20
and smoked out the leafy suburb where I had to stop.
I removed the filter, and EGT's dropped back to a minimum
and no more smoke, even after 30 minuets at maximum velocity.
Turns out that what I thought was a failing turbo was lack of maintenance

Thinking back, It first started giving trouble on the way up to Coney Farm, also when it was chucking it down.
http://www.candrenterprises.co.uk/shop/air-filters/" onclick="window.open(this.href);return false;
1 K&N Replacement Air Filter VW Transporter 3 24 80-92, 1.6 ( 74 - 92) Turbo Part#: 38-9103 £40.26 £40.26
1 K&N Cleaner and Re-oiler Kit Universal - K&N Cleaner / Reoiler Kit Part#: KNCK £9.14 £9.14
Subtotal £49.40
Delivery £6.25
ORDER TOTAL £55.65