europa - Europa - The best solution for you would be to ask BB to send you a replacement Expansion Valve. It should not be a hard thing to change, and it’s very accessible from the top.
You might even get away with replacing the internals of the expansion valve - which would save you the hassle of unscrewing from the fitting and re-sealing with PTFE. Saying that… Eventually things like that will happen, so it’s always a good opportunity to deal with it. Take my example: The group solenoid started to “chatter” - making a horrible buzzing noise. All it is is the very unfortunate thing that some debris got trapped in it. I had no choice but to get on with it: Remove the top, sides, tank assembly, disconnect some wires, undo the solenoid, clean it and then re-seal it with PTFE very carefully, and put all back together again. I’m glad I did it. Although laborious, it’s rather rewarding and gives me the sense of achievement and the confidence that I can also deal with other things. After all, it was that difficult. Replacing the expansion valve would be a lot easier than that. :-)
Keep us posted.