last service unknown sparks likewise...
Hmmm, I am not surprised it failed on emissions then.
Please please take care in your car and invest proper money in keeping it going. These cars are rare enough now and they do require proper care.
I would prescribe the following:
Immediate cambelt + balance belt and tensioner change if you have no record of it being done in the last 32'000 miles/3 years.
Replacement of Variator if you hear a rattle at the top end.
immediate Replacement of Oil + filter with good quality 10/40w semi synthetic (I recommend Millers XXS)
Replacement of Air filter element.
Replacement of all 8 sparkplugs, ONLY with Alfa OEM spec plugs.
Replacement of Thermostat, cooling system flush and inspect the radiator for condition.
Diagnostic scan to check condition of Lambda and MAF sensor. Replace sensors as necessary.
I'm afraid you are just about to learn that there is no such thing as a cheap GTV, the above work will cost you a minimum of £500, likely nearer £1000 but it will pass the emissions.
Out of interest, How long have you owned the car?