I've spoken with the behaviourist.

[Mel]

We had quite a long conversation and from what I have told her, she believes Tali has a territorial issue. Of course one of the ways around this is to desensitise him to what appear to be triggers; the noise of the lift, the letterbox, the door buzzer, doors opening and shutting and sometimes keys. I'm going to have to firstly try to record these and put them on cd and play over and over, using treats when he is quiet, plus re-enforcing that behaviour at all times. Apparently as he becomes desensitised to each noise, it will become more apparent as to if there are further problems, as he may try to replace the barking with something else. However if it is purely just guarding and he habitually barks at these noises, then with each noise reduced, Tali will be more confident and cheerful.

She also heard the fireworks going off down the phone and that Tali was quiet and this seemed to prompt her to say she felt he was not noise sensitive. She said if I struggle to call her in.

[Geordietyke]

Well good luck with it Mel, at least you know if you try this and it doesn't help, there is someone you can call in.  Lesley 

[Mel]

Well Lesley, it was getting some sort of idea as to what the fear/reaction was. I wasn't sure if it was just noise based, but obviously after the fireworks, I could tell it wasn't just noise. Plus my neighbour was talking yesterday, not the lady next door but across the hall, and he said that Tali seems so worried at the lift. When I've been out he's been quiet except when the lift goes, which is the first time anyone's told me. Just needed a professional to give me an idea as to what it is, afterall, he's generally a very good dog, but having never experienced any territorial behaviour in my dogs before I wasn't quite sure how to tackle it. However, it was becoming apparent from the fact he still barked in the Thundercoat, Calming Band and with ttouch, that this wasn't actually nervousness over noise. So I'm going to work on the process of desensitisation, which can do no harm, and see where we go.

[lindseyp]

Sounds like a step in the right direction for you both Mel & pleased you've got someone onboard to give you the support/advice you need. Hopefully the behaviourist will indentify Tali's problem & together you'll be able get it sorted & your precious boy will be a happy, relaxed pup once again 
Good luck Mel - thinking positive thoughts for you & tali