Forgive my confusion, but how does a £700 frameset fix a wheel issue at all?
Do you mean buying a whole new bike? Cinelli Mash comes as a frameset, not a complete build, my estimation is that the new mash bike on the cinelli flickr would cost at least £1300 to build up, probly a fair clout more. The '10 frameset is about £650-700. Also the forks arent drilled for a brake, well, they are, but then the hole is re-filled with a softer metal and the paint job applied over it, its so brakeless riders (such as the background that the frameset comes from - look-up/buy/download the mash movie/feature length video of people messing about doing tricks, riding like maniacs and skidding around in san fransico on fixed wheel bikes) can have a nice clean looking fork, those that value life and limb need to carefully re-drill this to fit a front brake. If you really are interested in Cinelli frames, TokyoFixedGear and Velodrome shop both deal in them.
Wiggle stock some frames (Gazetta, Vigoreli) but not the Mash.
Personally, I think the Masi bike looks nice, I dont know anything about the brand but they look pretty nice bikes and with a nice set of wheels would serve you well for a long while, again though, your choice of wheels can be based on many factors but mostly it will depend what sort of riding you do, and roughly, what you wanty from them?
If you dont mind people shouting "do a skid" and pawing over your bike and telling you how awesome it looks get some deep V's, b-43 or H+Son EERO or something alike, these rims are all pretty bomb proof, good for tricking on, so as a by-product excellent for commuting etc because pot holes wont touch them, but they are heavy. If you want something fast and reasonably light with an aero profile rim, the mavic ellipse will do great. If you want true light weight you may have to forgo the deep section rims and take something like an open pro, excellent rims too. All depends what you do with your bike, how much abuse it takes, the type of riding you do.
Im pretty much of the opinion that people often over complicate the buying of components, being relativelly feckless, I would buy the wheels that I thought looked the nicest, so long as they didnt get poor reviews or werent totally impractical. At the end of the day, most of us derive very little from the performance perks of our componentry.