Just curious but something does not add up here - you posted the first message beg. July about being tested - then today post your viral load is undetectable with a CD4 count of over 800 - just 8 weeks later. Exactly what hospital is treating you? With a CD4 count of over 800 you should not even be on treatment and certainly not within the UK, yet the only way you can have an undetectable viral load is to be on treatment.
To go from a detectable viral load (which would always follow a positive test result) to undetectable takes about 2-3 months, yet in the UK they wont start treatment unless CD4 is in the region of 350.