I have two implatns done in Poland, but I done it at family dentist so not much of a risk there. One cost about £1500- £1700 not including flights and you need quite a lot of flights (about 5 years ago).
I needed 4 visits (check-up and removal of teeth, checkup, taking form for new teeth, inserting of screws in jaw, checkup screwing the teeth in, cheekup, fixes made to the implants as the jaw aligned).
Also you would need to calculate not only flights but hotels, taking time off work to do it, etc etc. I don't know if at the end of the day it will not come to the same amount as doing them in uk?
I was organising weding at the same time as going to dentist, so it was two birds one stone situation for me.
Also I only had two done, can you check with a dentist if they can do something to strenghten your teeth? Is there any other solution? I can assure you that puttin implants in is not enjoyable experience.