Yes - sounds reasonable to me - don't use one myself, and haven't got a car anyway. Each to their own as far as I'm concerned.
Only thing that crosses my mind is that even with a pager surely it's still 99% sheer luck to be in the right part of the country when the alert comes through ?? - as you said '' good fortune to be in the right place at the right time''
Is it not equally possible that one of the Pipits or Larks could have flown in the required direction and given you the lead to the Harrier ? thus rendering said pager redundant ?
Perhaps at this point I should say I'm aware there have been 1 or 2 'caustic' comments on this subject and I'm not in away way trying to get into that. Just my thoughts.
Would be very interested to see your East Anglia trip report Jason