Thanks to Hypertech and Mr F for sorting out the knock spike.
Car had develop what I can only describe as a spike in the knock level ( highest was 85) over 6k revs on full load with occassional overboost.
Duncan checked the simples things first fuel pump & replaced filter. Then ran injector cleaner in case the was a slight blockage. Still no luck so on the rollers, injector duty was fine but was running a wee bit lean top end. Tried a new Maf (best deal was Roger Clark) which brought the knock down to about 60.
Duncan thought great were getting somewhere, smoke pressure tested the system and found a tiny leak in one of the vaccum pipes sealed the hole thinking this would sort it and level had gone back up to 80.
Next injectors were taken out, 1 was slightly down but nothing to cause a problem, spray pattern wasn't great so a good clean and new seals.
Car was put back together and left as AndyF was over a couple of days later to map a few cars.
Andy checked the map and nothing had changed from when I had it mapped back in August. With the Apexi being eliminated Andy did a couple of runs in the car and tweeked the map and car was back to normal.
Only explanation is it was a combination of things Fueling, Maf and a leak. Anyway all fixed so a happy chap.
Until Duncan total me my coilovers are past their best. Going to have to break this one gentle to Mandy in the last month I've had Road Tax, Insurance, Mot, Hypertech bill, new Maf and new HKS exhaust.