I don't thrust those filters either.
You got a new MAF a year ago, but with that filter is already worth to take a look at the sensor inside and give it a cleaning. disconnect it first. I would recommend spraying or brushing the sensor with a very small and soft paint brush wet in isopropyl alcohol. people also use carb cleaner, but isopropyl alcohol leaves absolutely NO residues!
talking about MAFs, have you already tried to disconnect it, start the engine and see if the idle gets better? if it does, then propably you got a dirty or faulty MAF.
another problem with MAFs, is that the error codes displayed are most never related with the MAF itself. example, p0170 and p0130 are lambda error codes, but most of the times caused by a faulty MAF. and it's possible to have a faulty MAF and no error codes displayed too
just another thing. as long you get your alfa running, starting and passes the MOT, don't be stressed about repairing it. you have plenty of time to do it and could save yourself a lot of money. alfas are as faithfull and repairable as any other brand. just do the regular service and keep an eye on oil level - always on top!
I own 2 alfas. a 146 bought 7 years ago (is now almost 17 years old) and a 13 year old 156 bought last year to replace the 146. the 146 run 90000 km on my hands (180000 km now) and it is so great and so much better than when I bought it that I can't afford to sell it or give it away. I just love the damn car. the 156, made a major service when I bought it, still had some minor bugs, but passed the MOT faultless, so I'm dealing with the faults calmly, reading a lot on the forums and internet, and at the lowest cost possible. almost perfect now