thats not a bad price mate, depending on what ur having done. if your building a proper install with the false floor, custom box, etc etc £200 aint too bad.
ive got mine in for a install and its £350. but that includes full fibre glass box, false floor all set into the spare wheel well, completely wired with 4-gauge wire and directed RCAs. Its also gonna be layered in dynamat. should be interesting to see the result!