There is no formal 13+ at Tiffin boys, however, your friend may be right in that there is actually a plausible reason for not sitting the test with everyone else and trying to get in in subsequent years. This is because if you sit the test and do not achieve the cut off mark (i.e. the lowest mark that is offered a place) you are not
allowed to even apply to enter the school until the 6th form. (See extract from admission policy below)
"The waiting list will be maintained from 1 March until 31 December 2010. After this date, there will no longer be a list. Candidates who have taken the test but who have not achieved the cut off mark and therefore not been offered a place by that date will not be considered for a place in Years 7 to 11 at any future time."
If you don't sit the test, you can put your name on a
waiting list (not the
waiting list that applies up to December) and if a place comes up, you sit a test with everyone else on that list and let the best boy win!
It does seem crazy that you could be one mark under the cut off and perfectly capable of coping with the work at Tiffins, but you are not then allowed to even apply again until year 12. I understand that this is to prevent the school being inundated with children who "failed" the test sitting on the school's books waiting for someone to leave......
The same rule applies for Tiffin Girls
It is a risky strategy though, but I do know of a girl who did exactly that at Tiffin Girls and secured a place at end of year 7 (although in her case it wasn't a deliberate ploy.......)