Theres not a lot in price between all the major manufacturers. I've just priced up the following:
All around the same money, hard to compare as things like the tailgate is an option (!) on the Brian James and the ramp holders an option on the ifor! I think the above prices were with both tailgate and ramp holders.
In the end I called Buffalo trailers for a price, around 4k, but they had a s/h triaxle 10*6 tipper that had been thru the workshop for 2.5k plus VAT. So I bought that to see if I like having a tipper trailer, it's had new tyres, new brake cables, all lights and brakes work which is the main thing on a secondhand trailer. Nothing I can't do myself but that trailer has to be the right money for that. Floor is steel plated so although the board underneath is going in places it should do a couple of years then l'll flog it for new if it fits the business. I quite like it. It's clearly had a hard life, but has stood up to it well, 2.5k is about what I'd expect a secondhand 3.5t tipper to owe me if I bought it as cheap as they get and put it through my workshop so I'm happy.
Here's a beavertail I bought for £900 with new resin ply fitted (had to flip it over though! muppets put it shiny side up) Brake shoes were good, had two sets of ramps with it, I changed the cables, a bearing and put brand new wheels on it. Stands me in at £1600 including two full vehicle tie down sets, a spare wheel, new prop stands, new jockey wheel, box and a few other trinkets. Handy for bulky stuff and as a backup plant trailer than can handle all my diggers (just) Pro tip- if you have to change all the tyres on a trailer, then it's not a lot more just to get a set of wheels and tyres off eBay. I went for the more modern wider tyres/rims, and flogged the knackered set for £50.
My plant trailer I bought for £400, added a steel over boarding floor, new lights and a few extra tiedowns. Ran sweet for a year then I did the brake shoes last month. Buying trailers at the right money for the condition is an art, and it's hard when you're VAT registered as the s/h no vat values are stupidly high because every smalltime builder wants a trailer.
I seem to have ended up with as many old secondhand trailers as old secondhand vehicles, but you can't beat having exactly the right tool for the job plus spare capacity.