thanks for the replies so far.
decided to cancel the garage and new injectors. reading through i think there are two main reasons why it failed, the first is my driving if i say i drive for more mpg rather than speed, i change gears asap keep the revs low and keep the speed at 55 mph and below (i get 32 mpg). i work about 3 miles away so its short journeys mainly. the second is i don't think the engine was warm enough when the test was carried out, the test station is 2 miles away and i was told to take it about a 2 mile drive before the emissions test.
plan of action-
i have got a bottle of wynn's injector cleaner and i am going to blow the cob webs of the engine over the weekend, leaving it till 3000 rpm and over between gear changes then when i take it back for a retest i will take it on the motorway to get it nice and warm and give it a little thrashing. if that does not work then i guess it is new injectors after all.
question about the injector cleaner, it says put it in the tank but the tank is 3/4 full so it will dilute quite allot. is it ok to put it in the fuel filter neat?
paul.