There are quite a few apprenticeships in London. EY and JP Morgan currently have their applications open (however closing at end of November). Equally, Deloitte have their locations in London open right now. Also, there's PWC Accounting Apprenticeship which you need to apply to via UCAS (the others have separate applications). Deutsche Bank will be another one to look out for.
Hope this helps. Let me know if you need any more information.