Advice on Off lead/ On lead behaviour

Okay so we have has Woody now for a few months and he's doing well with his training etc and is perfect inside the house which of course is great, I just need a bit of advice on his behaviour outside the house. Firstly is his problem of charging up to and into dogs. Its strange because once he's done this he runs pretty much straight back to me unless the other dog initiates play. I have bought a 10 metre horse lunging line/ training line to try and sort this out to stop him from running off until I can get his recall to be 100 percent reliable when there are dogs and other distractions about , as it is already excellent when there are no dogs around, but I still have issues with trying to get his attention off the other other dogs and onto me. I bring treats and foods which usually get him back but as soon as I give him the treat he tends to concentrate back on the dog again so can anyone suggest a way of keeping his attention?

Another issue I have been having is that he stalks other dogs whether he is on lead or off. For example of he sees a dog across the road he will become obsessed with it and start walking slowly passed it while staring at it intently. When we approach other dogs he does it as well until he gets to the dog. If I let him greet the dog he is fine so it's not like he is being aggressive and I don't think he is being submissive. So he basically does that same thing that a lot of collies do when they approach other dogs. If he is off lead he usually starts stalking the dog then stops for a second or two then charges at full pelt at the other dog. Again has anyone got any advice on how I can keep his attention on me rather than the other dogs and at least ignore the other dog or approach normally. Even if the other dog completely ignores him he will still do it, not every time he sees a dog but enough for it to be a problem. Since I got him at about 18 months I don't think he was socialised at all which is probably why he doesn't know how to properly greet other dogs but it's a shame because he's great once he's met the dog and will either play with them or ignore them.

Thanks everyone

Unfortunately I have very similar issues with our 2 so I tend to try and keep them on lead whilst other dogs are in the area unless we know them and then it's playtime. Tilly has come off badly a couple of times when she has been off lead and a dog has come charging out of nowhere and having a go at her , but bless her she doesn't get so aggressive just defensive. I like to keep them both off lead as much as possible when they are out but always in my sight , it's a shame other people don't always think the same

Rocky does the same stalking thing with other dogs too. It seems to be usually with dogs he doesn't know though. I now try to get him to sit until the other dog has passed by and try to keep him concentrating on me with a treat or toy.

The watch command would maybe work well for you too here, just use the word Watch and get him to watch you until the other dog has passed by.