I had similar done by Ramesh @ Bridge Dental
Not particularly cheap but painless and very good standard of care.
... Pickering's on Upper St. Islington is NHS... I still go back there after 30 years... Ola (he's Norwegian) is the best... he specialises in minimally invasive dentistry...
I can also recommend him, he is very good.
Many thanks to all who took the time to give recommendations. In the end my dentist referred me to Maria at Endoclinic in Cockfosters http://www.endoclinics.co.uk/ I was happy with what she did, and she is a nice down to earth lady. Just had 3 month check up and all is healing well.