Wow! I don't want to jump on the bandwagon, but we are slowly (and rather dimly) realising that this is an increasing problem with Buddy. He is also becoming more wary of strangers and a bit hand shy.
I have a home made long line (made in an emergency when we had Salty with us in February) but it's not as good as a proper one. And I didn't know about the harness either.
To be honest when off lead Buddy rarely goes up to the dogs he's scared of so it's not really going to make much difference there. He tends to hide behind me. but when they have passed by he might be a bit bolder towards their back end!
When on lead though he's a nightmare; barking and lunging. So much so that I try to avoid meeting other dogs in the street. Especially when I'm on the school run because the barking scares the kids as we walk past, even though it's not aimed at them.
I have been thinking about some 1-1, but have been trying a bit of distraction on my own with a little success (which might be down to my technique).
I will be watching this thread with interest.