You are quite right (but too hard on yourself). I have changed the co-ordinates, thanks.
I've recently found this page on the OS website very useful:
http://leisure.ordnancesurvey.co.uk/leisure/searchProcessing.jsp?q=sk061671&gazName=g
The search facility is very good as it brings up named barrows etc as well as place-names.
Thanks,
TMA Ed.