Fishing UK Which are the best ledger stops ? The ones I have are useless sliding up and down the line. Thank you in advance?

A decent split shot with two float stops one either side. Make sure the shot is the right size for the line. To big it will slide, to small it may snap your line.

I apologize if this is not what you mean. Ledger to me means using a lead to prevent the fish from running. I normally use a safety clip and adjust my hook-link to allow the fish to run only so far before feeling the lead. Sometimes I use a very short link so the carp get hooked immediately and other times I like a longer hook link up to two feet long. If I am letting the fish run without any weight, then I normally try not to use a lead or I do not block it at all. If you want the jerk effect on a run, then you will find that any kind of float stop you use will always move up the line. You could try a leader and put a swivel as a stop. Then the lead could not pass that point for sure and cause that jarring effect to set the hook without anything moving up your line.