Seems so ironic that you now have to pay out hundreds of pounds to a dentist to fix issues that were caused by bad dentistry!
I hope you get it sorted soon. The dental practice I used (I believe they are a national chain, happy to PM you details if it would help) were fantastic. I'm so happy with the results and did feel like they actually listened to me. Payments wise, they offered various payments options. They also seemed clued up about diabetes, which really reassured me.
Take care
Em x