Have a look at Bailey's website, there is a list of all of their servicing dealers there.
Try clicking on this link http://www.bailey-caravans.co.uk/retailer-network/uk-network/
or put Bailey caravans into google (or your favourite search engine) and find their website that way.
If your chosen dealer is as busy as mine then be prepared to wait 6 weeks or so for a service and also expect to pay around