Hi Steve a late reply, however due to a poor Haynes manual, I couldn't find the Boost sensor. However going to your second part of advice, I removed the MAF sensor and gave it a good clean with proper cleaner, next morning took car out took it up to speed which it normally goes into limp mode, engine gave a bit of a stutter close to where it goes limp then ran ok, no more limp mode? Strange as no errors shown on MAF sensor?
Regards the Boost sensor, having for a copy of the VAG manual, for my A3 it shows a solenoid box with 6 pipes attached and says the boost solenoid is further on the left of solenoid box, whereas removing the fuse box cover will allow better access to booster.
So much for the Haynes manual which also gives directions to the booster from drivers seat. So much for Haynes gone into bin.
However all appears to be running ok. Many thanks for your advise given.