We got a border collie from a rehoming centre about 5 years ago. At first, he couldn't be put on a lead and walked properly, he would scramble about but now he's a lot better. Anyway, I just have a few minor problems and I was wondering if anyone here would be able to help:

1. When he sees another dog, he will lie on the floor from quite a distance away and refuse to get up. I've tried breaking his stare (putting my hands infront of his eyes), trying to distract him with doggie treats, trying to pull him in the opposite direction etc all to no avail. He sees the dog, lies down and if I pull the lead, he will let himself literally be dragged. Still refusing to get up.

2. He won't come back if we let him off the lead. After a couple of instances where he ran miles away we decided to build it up slowly. Firstly taking him on a long walk then letting him off to come to us from short distances away (with doggie treats - although if he's outside he doesn't care about them). We gradually build it up to bigger distances. Then one day even after he was tired out from a long walk we let him off and he ran away. Again. And we had to spend hours looking for him. He was too tired to run far and only ended up in a neighbours garden. Since then we've never let him off for fear he'll get himself run over.

3. He pulls really hard on his lead. We were told to get a 'gentle leader' which tightens slightly around his mouth if he pulls too hard. And although he is much much improved with this, he's still a big puller. If I'm jogging with him, he'll still pull really hard regardless of the gentle leader. And I do feel a bit sorry for him because a couple of times its rubbed a little hard and around his mouth has been a bit inflammed.

My dad took him to dog training classes but because the dog couldn't calm down, they basically asked him to separate him from the other dogs into another room. After weeks of classes there still wasn't any difference in his behaviour. Anyway, just wondering if anyone had any good advice?

When we take on a rescue dog we can sometimes take them into our homes feelin sorry for them. This a huge mistake as they read us as being very weak. From day one we are viewed this way and creating a leadership role becomes very hard.
I suggest you follow the thread I have posted on rebalancing the leadership roles within the house. Your dog seems to have very little respect outside the home so i think it might be a good place to start.
Recall should be done with a very long leash. It allows the dog to roam but you have control in retrieving it.
Remember you picked a collie, and all it's behaviour really is just an exaggerated natural instinct.
Laying down suggests it's herding instincts in use. does it show any aggression whilst doing it?
Also when your dog does this do you stop turn and look at her?
If so it's leading the walk. I do You follow!
When the dog drops try to keep moving. If this doesn't work catch the dog before it drops and set off at a sprint past the other dog. Key is to interupt the dogs pattern of behaviour. Dogs can't think of two different things at once. if shes running she might stop dropping.
Also if you can catch your dog befor it drops spray pet corrector near her rear end. this too acts to interupt behaviour.
Remember keep moving forward, you'll most likely add to this problem, because every time you see a dog coming you expect it to do it. Dogs read us and she 'll think that's what you expect. Say to yourself" see dog keep moving" over and over.