Right tonsil much bigger than left. unknown as to how long. asymptomatic. gp didn't even consider cancer. could have been enlarged months/years?

Yes: Either you or someone else with the same concern has written several times before with the obsessive idea that having one tonsil larger than the other means cancer. Both i and several other people have done everything we can to reassure you. This is a common finding in perfectly healthy people, and chances are that they were like this long before you first began staring at them.