Never thought getting this done would be sooooo complicated....spoke to Withington cycles who do indeed offer a powder coating service, they send them of to some guy in Cambridge, turn around can be anything upto three months (!) but price isn't to bad at £85.
Also been in contact with leominster powdercoat, own website and have an ebay page, waiting to hear back. The quality looks preetty good, they get great reviews on some of the MX forums and the turn around seems pretty sharpish! Promising?