the best thing you can do is ring up the large phone operators direct, haggle with them and look around online and in local shops such as CPW and see what they offer, you have to do a comparison shop in this case.
if you see anything which is a bit pricey but gives you cross network minutes or extra texts ring the operator O2 t-mobile etc direct and ask them about their packages and tell them what you want and have seen, you might get a good offer thrown your way.
http://audiovisual.kelkoo.co.uk/b/a/...ct_phones.html
the above might help.