Thank you for all the lovely replies

I'm sure it's more down to Louis than me because once he started to regain his confidence it became much easier for me to remain calm and positive in potentially bad situations too. I'm beginning to enjoy my walks again

Maria (Rubydoo) has also been a great help and a confidence giver to me and Louis through all this. She uses the "watch me" technique on Louis too and has always been there for me when I've felt really down or when Louis has had a setback.
Maria's dad has also helped in getting Louis calmer around men he doesn't know. Louis has only met Maria's dad a couple of times when they've both been at Maria's house at the same time. The first time Louis had a bark and a growl at Maria's dad when he walked into the house so Maria calmly shut Louis in another room, got her dad to sit on the sofa with a cuppa and got him to ignore Louis when he was allowed back in. It was enough to relax Louis and since then they've made further progress through a mix of not approaching or making eye contact with Louis and randomly throwing a treat or two towards him. I'm not sure if that's what a trainer would advise but it's worked and Louis is now confident with Maria's dad.