This is probably going to seem a bit harsh but I assume that you are a B1 or B2 and not an A licenced person. An A licence is, in my view, just a certifying mechanic with limited capability and you might aswell stop reading now.
If you are going to tribunal then you imply some form of dispute, possibly to the point of dismissal.
My opinion is that you have no grounds. A Licenced Engineer, B1 or B2 is just that and it is the same qualification, Line or Hangar.
I am assuming that you are a Line Engineer that your employer has seen fit to move to a hangar environment, tough.
You should try, and if you don't "Like" the hangar then attempt to return to the Line environment, if this is refused then move on.
"not fancying" something is no reason for a tribunal to look favourably on unfair dismissal (reading between the lines)
I write this as someone with 30 years of line work forcibly moved to a Maintrol position which I didn't fancy, but two years later find even more of a challenge than line work for this B2.