Hi, on this Board there are quite a number of topics such as
this one, where you will see that a failed asylum seeker returned to their country and successfully obtained a visa to return to the UK. Here is
another example.
So Elias whilst it would be wrong to say that it is a risk-free plan, returning to your country to apply for a visa there, the evidence shows that with the correct supporting evidence being presented with the visa application, it is most certainly possible to succeed in getting the desired visa.
Q7.7? Other opinions very welcome but based upon what you say I think you can answer "no" to that question.
Just a general point, and I am not suggesting for one moment that you would do otherwise, but do ensure that all the answers to the questions on the form VAF2 are answered honestly. For example, Q7.5 needs to be answered "yes", based upon what you post, and accordingly more detail needs to be entered into Q7.9 to Q7.15.
The birth certificate problem? I would suspect that the BHC in Sri Lanka is well aware of the problem, and probably faces it every working day. Just document the problem and include a statement saying where you were born, date of birth etc.. Presumably your passport shows your correct date of birth?