guys just to update you all on this !
Gas4u was bang on with the problem, but due to the customer constantly resetting the cumbustion panel was blown off with the explosive ignition and burnt right through to the back of the thing and cracked the back casing on the boiler, new boiler required...
very scary to look at apparently, this thing is only 2/3 year old and has been 1 problem after another but to burn right through and crack the back of the boiler is unbelievable.. very scary, so glad it was turned off as this could have been disasterous !!!
gas4u, cheers for the advise our engineer went straight to this and will be well and truly noted for future isses with LF fault / explosive ignition and high combustion readings..