Here is my perspective from Air Canada; as an Aircraft Maintenance Engineer, I am represented by the International Associaction of Machinists (the I.A.M.). This union also represents all of the ground handler types, bag smashers, cargo guys etc. The un-skilled rampies are in the majority in our union, so guess whose interests get priority?
We have formed our own association now, the "Canadian Aircraft Maintenance Association", and are presently involved in the process of application to the Minstry of Labour to have our group certified as the official bargaining agent for Aircraft Maintenance personnel.
With Air Canada having slight financial woes at this time, the timeline of our battle is uncertain, but we are determined to have our own representation.
I have heard stories that some years ago, an offer was made from the Air Canada pilots to have the Engineers join with the pilot's association. I don't know if this is true, but I doubt it. Why would the pilot group wish to dilute their own group with ours? It would put them in a similar situation as having our Engineers grouped with the bag-smashers.
My advice to the Engineers in the U.K. is that if you're not happy with your present lot, then work to change it! It can be a long and bumpy road, but worth the effort.