A.
Hi An accurate answer could on loy be given having seen exactly what you present with and how complex it would be to fix but I’ll try to give you a guide.

I’d also suggest that if you want the very best treatment done and the best result with Lingual braces please consult witbh a specialist orthodontist who has a lot of experience in using these appliances

For more complex treatment and to treat all the mouth then Incognito braces or something similar, woudl mornally cost from £5000-10000.

There are treatments available to just treat the front 6 teeth, one being “Social 6” braces and this starts at about £2500-£4000, again depending on complexity

One thing to be mindful of is that the most expereinced , most qualified dentists will have higher fees in general to those less experienced and in orthodontics, experience is very important for you to get a great result that also lasts!

Here’s a recommendation:

http://www.umbrellasmiles.com/london-orthodontist.html

Hope that helps

Mark