Where to retake A-Levels at 18?

I have completed my A-Levels this year and want to retake, but I need to be in full time studying for housing benefits and stuff, so I don't think I can be a private candidate. I need to find colleges or sixth forms that let me start at Year 2 because I don't wanna waste two years instead of one. I am 18 as of now and do not turn 19 until the course ends next year and still funded by the government for education. Does anyone know any colleges or sixth forms in London that allow this? For extra info, I got good GCSEs was getting straight As and got many RG offers, but i fluked my actual results.

Many thanks!

Surely you should wait for your results before thinking about this because you don’t know how well you have done yet ?