There are number of people here that started as you did and, despite early resolutions, are now confirmed cold water divers. Unless you are absolutely sure that you won't be diving around the UK (never say 'never') then just go and buy any light-weight bc and reg (places like Divers Warehouse sell 'Red Sea' packages that should meet your needs). If on the other hand you'd think that there might be some possibility of a bit of UK diving (which will then turn into a lot), then yes, go for something more substantial - it may weigh a little more but you won't find yourself having the expense of an upgrade further down the line (and we've all done that!).
If you want good deals on a package then get the dive show at the NEC next weekend. Alternatively see what can be had second hand from YD'ers - lots of us have kit that is just knocking around after converting to UK waters.
