There are 3 stand alone CGM's on sale in the UK Medtronic,Dexcom and the Navigator. If you are having a pump and want a CGM why on earth don't you choose a pump with CGM compatibility, this would work out a lot cheaper for you. Animas and Medtronic are CGM compatible.
how much would i be looking at to purchase a CGM device?
edit: found the price.. very expensive lol
Initial cost - for the hardware such as the receiver and transmitter - varies from around £1,000 to £2,500.
If you have a newer Medtronic pump you may find CGMS is already integrated or may be available if you pay a supplement (around £200).
Running costs
The main ongoing cost is the disposable sensors, costing around £40 - £60 per sensor, with each sensor lasting a recommended 5 - 7 days. Many users find they can wear their sensors for longer than the recommended number of days.
In some cases you also need adhesive covers to keep the sensors in place or protect them from water.
You may also need to buy semi-disposable components such as transmitters every 18 months or so.