Nothing really to add here at all. About the UAS thing and lack of ATC, all I would expect is that you would have to have good answers at interview why you did not join the ATC, why you failed to gain a place at UAS, what you learnt, what you learnt from OTC and what advantages will your time in OTC bring to you and your future career.
Simply they are all 'begging' questions for which you should prepare answers.
The answer you gave for ATC will be an openner for further probing questions:
What did your parents think about you joining the OTC? What do your parents think about your application to join the RAF? They would not, I guess, expect you to say you hadn't told them.
No, you are doing all the right things which goes some way to answer the what you learnt question
good luck, don't bust a gut for a 1st at the expense of your life.