Are you sure you have the correct model no.?
The earlier CMT routers are similar to Elu/DeWalt/Trend ones, the later ones look to be made by Triton (or their manufacturer).
If it's an earlier one, most parts are available from Miles Tools in Yeovil.
But a common problem on the Trend T10/T11 and DeWalt DW625 units (which along with CMT seem to come from the same line), is the speed control magnet coming loose on the shaft. That might well give the racing problem, although I can't explain very slow speed thereafter.
It's an easy thing to check yourself. Unplug the router and remove the end cover. The speed control magnet is a brown/black disc on the motor shaft, about 20mm diameter (possibly a bit less). It should be secure on the shaft, and surrounded by the speed controller module (black plastic shape with wires emerging). If it's obviously loose, or there are circular scuff marks on the inside of the cover, you can remove it, add a smear of Loctite, and put it back. Leave for an hour for the Loctite to harden, and try it again.
If that's not it, the speed controller module can be easily replaced (DIY job - there are no special tools or complexity involved), but it's not cheap (70 quid -ish last time I looked).
There's not really anything else that would give those symptoms, although the actual speed adjuster is a carbon-track potentiometer (an "edge wheel"), and they are fairly notorious for going intermittent. Try gently working the adjuster to and fro (from fast to slow and back again), a few times (10 or so). That may clean up any muck that's got on the carbon track (you can't get at it to clean it directly, and anyway that's not a good idea really).
If it's the "Triton" type all bets are off - I have no idea about the innards of those, and I note that CMT seem to have added quite a few other designs to their range recently, so it could be different yet again. Chances are though that if you can identify the other models/brands its sold as, you can find spares cheaper that the importer's prices.
Hope that's useful (but I realise it probably isn't).
E.
