You are right about the additional charges (delivery if you want it delivered from another location and a PDI charge which includes badly fitting mats) however they are not massive and you can always get at least £300 off the advertised price which more than outweighs the additional charges.
They are sometimes imports. I have bought a Renault Laguna from there before, pre-registered the day before I got it with 10 miles on the clock for £8.5k below list price.
I also bought this Brera from them (part ex'd the Laguna) '59 plate 2.2JTS, 11k miles, Pelle Frau red stitched leather seats / steering wheel, red 'Alfa' calipers etc for under £14k and this is a UK car.
Admittedly, you need to watch what you buy but you can find bargains at Motorpoint, just avoid the extended warranties as they have very low caps on them.