Callum,
With something like this, if you don't try you'll regret it as you'll never know 'what might have been'.
I went through OASC in 1970 and failed, to be told to come back in a while and try again. In the ensuing period I found a job a loved, and a lady to go with it, so never went back.
However, I did end up with a great career in the offshore industry that gave me a challenge every day, and, eventually, the funds to earn a PPL.
As the others have said, try it and see what happens. If you need to make multiple attempts as MPN did. If nothing else it shows the reviewers you have the tgenacity to keep going after something you think worthwhile.
Good luck!