It may not be as bad as you think. There is a maximum price on the NHS per treatment (per amount of work that needs doing) & that price is about £380. Crowns, fillings, etc will be covered on NHS. Bridges, implants, etc will not be be & will be charged at private costs......then you should start panicking.
Considering the amount of work you likely need, I don't think that's too bad.
And I say that as someone whose teeth are not the greatest. I'm looking at implants & even with a trip to Turkey, we're talking thousands.