Old fashioned chunk of metal sticking out the back 24/7 = a Flanged towbar. I prefer this type its cheap and works well. Easy to fit extra's to it or change the ball.
Swan Neck is a ball on a shaft. Bit dearer. My dislike on these is if you damage the ball how long will it take to source a replacement?
Then you have the removeable or detachable, Which can look like a swan neck one but you can hide it when not in use.
I dislike these for the same reason as above. With the added downside that you can also lose it.
Depends if you want it visible when not towing etc.
Also each manufacturer will have its own variation on the fitting. Some require a cut to the bumper and others may not.
Some car designs dont give you a choice. Bumper cuts ca be visible or invisible like the undertray or similar.
Grampian91 - I have a Witter detachable, for a couple of reasons.. the first is the big reason.. my car wont take a fixed tow bar, its detachable of nothing.
A positive with the Witter is that the towball / detachable part is the same across most models so its not a problem sourcing a new one.
In regards to losing it, its possible but its heavy and mine lives in the spare wheel well.
I'm not sure whereabouts you are in the westcountry but we used Somerset Mobile Towbars, they are based in Bridgwater. We had a VW Passatt and got quoted £700.00 at the dealership, these people did it for less than £300.00, service was very good as well.
Make sure you shop around and get plenty of quotes. I was stunned at the different prices for the same job when I rang around. The cheapest was less than half the price of the most expensive.
Have to stay on the site we store the van this year (and probably the next 3). Not permitted to have the bumper cut to fit a tow bar...Never mind. The Cotswolds can wait for another couple of years.
Thanks to everyone who helped out with ideas and suggested places to get quotes