Just had a look at their website. Can't book flights through it, but did run an airport car parking check thru' it. It directs you to "holiday extras" website and i found it to be £4 dearer for a four day parking price than the comparable price thru' Bristol airport's own website.
One also has to be careful booking flights only thru' some agents, as Ryanair and Ejet sometimes only allow bookings thru' their websites. I think the likes of Thomascook and Thomson's are OK. I also know of a mate a few years ago who booked a cheap flight thru' a local t. agent, it was with an airline which was a 'rookie' and it went bust...whoops!
I'm sure they're fine, but in current climate i'm a little wary.