For most of the hand-held work required for a cabinet, you don't need a plunge router and you don't need much horsepower. I find that plunge routers are more difficult to deal with than fixed-base or D-handle routers. My Festool OF1000 is probably the only exception to this rule... but then again it cost a small fortune, even with the huge discount I got.
I'd suggest looking for a laminate trimmer, like the one suggested by acevedor2. If you have to have a router, buy a small one. Say something in the 1000w range, if possible. They're much easier to control for hand-held work than a larger 1500w or 2000w router. If you were in the U.S., I'd tell you to look at Bosch, DeWalt, or Porter-Cable routers. In the U.K., I'm not sure which brands would be available or your best bet. In general, I'd probably try to stay away from the very cheapest routers. With many tools, you get what you pay for. A cheap router may have little power, a collet that makes it difficult to secure bits, lots of vibration (= bad cuts), or a lot of run-out as the bits spin (= bad cuts).