You might want to get in touch with Pam who suffered for years until she got her amalgams out. She now runs the helpline in the UK.

http://www.pamshelpline.com/

I don't know how they test for sensitivity. Biolab in London do it through a blood test, but NHS might do it through a sensitivity patch.

From what I have read, if you test positive for the sensitivity, they will remove the fillings for you. However, I don't know if they follow all safety procedures. This is something you will really have to enquire about or try and get NHS sponsoring to allow you to go to a dentist who does. I don't know if that is possible, but if you test sensitive, you don't want them to just drill out the mercury without giving you oxygen etc. You also might want to insist on a biocompatibility test to make sure you are compatible with the alternative NHS fillings, which are probably not as good as diamondlite and some others available privately.

Please update with how you get on!