Crikey that's the deal of the century.
The place 3 hours from me - the most local - wants hundreds per filling, not including replacement!
Like you, i'm afraid of sinking so much money into not feeling much different afterwards.
Although i'd rather have something safer in my mouth than mercury and plan to change them just for that reason.
Please email me the dentist details so that i can inquire if i visit the UK this year.