First post, hope it's in the right department!

Anyway, got the dreaded ESA50 recently, which I'm completeing as it has to be back in a week's time. My memory's not too great, I struggle to remember details, and am not very confident on the phone. Should I;

Not put my telephone number on the ESA50


Put my tel. number on the ESA50, but put a note on saying that because of the reasons I mentioned, I would prefer it if they communicated by letter

Does anyone have experiences of not putting their number on the phone? Does it cause problems?

Any help, advice and experiences welcome and appreciated.