Quite possibly the best indoor aerial on the market, Eddie - still crap, but the best for indoors!
Have a look here:
http://www.wolfbane.com/cgi-bin/tvd.exe?
Put your postcode in and the height of the antenna above ground level (if it's an upstairs bedroom, 7 or 8 metres, probably..).
Wait for the database to run and you should get your local transmitter site come up - probably Black Hill.
Have a look in the "Field dBµV/m" column - if it's anything below 50dBµV/m, I wouldn't bet too much on it! You might get lucky if it's above 40dBµV/m and find many of the groups of channels (multiplexes) are just fine.
Here, for example, 1, 2, A and B are all fine - but C and D require better than an indoor aerial.
Hope that helps!