I haven't bothered with either app. The Covid Track and Trace App feels a bit intrusive for me, following me about! Places are so relaxed now that if asked whether I have checked in (ie used the QR code in a hotel, cafe, pub etc) I just say yes and they are happy. If that doesn't work I say no and give name and contact number manually.
The new NHS app seems to be of no real use to me until such time that I need to prove I'm fully vaccinated. I cant foresee that need at the moment but if I do I'll download it then.
So, my advice is not to bother with the apps, especially if they are likely to eat up data or cause confusion, and see how you get on.