I'm not keen on using the app either, though for different reasons. The new app is now based on the Apple/Google models I believe and less centralised than the government's original plan. The trouble is, even their version is apparently not yet as accurate as it should be. So it may tell you...
I’m very COVID cautious - but I’m also craving the opportunity to do something even vaguely enjoyable. If it’s set up as carefully as they’re planning, I feel it’ll probably be about as risky as going to the supermarket. We’d probably cycle to avoid the public transport, as trains would worry me...