Jon, I had to look at the compass bearing twice (then realised !!).
Judge and others make valid points.
Within this budget, the GPSW 2610 bike bundle will give you the 'boxed' 2610 GPS unit, RAM bike mount, RAM cradle, and power/audio which is 'bang on' budget. If you lower your sites, the Quest bike bundle with RAM mount and cradle is £360 in round figures, in a few weeks add a power lead, then I expect the 'real' differential to be nearer to £200.
The decision or dilemma is .. it comes down to what 'you' want, and its personal choice, and that it suits your needs. I continue to see either the 2610 or Quest as being the two main popular choices. So I guess your choice is which one and how much you 'shell' out.
RAM-man