Hi Simon and welcome to the forum
There are a growing number of fellow UK BBQ/smoking enthusiasts on the forum and we also have the benefit of the vast experience of our friends from the USA and elsewhere. The forum is all about sharing knowledge and experiences and from your introduction I think you will be able to contribute positively right from the start. Although there is a lot of discussion about BBQ hot smoking here there are also a lot of other passions - like cold smoking and sous vide. You will also get a lot of good advice on food safety here. The forum follows the USDA guidelines, however they are very similar in most respects to the UK.
Like you, I started out many years ago on the Weber Kettle and it is a very versatile smoker that I still use regularly today. It is obviously good for grilling but from the Weber courses you will have seen how good they are for indirect low-and-slow too. I went on their "Thrill of the grill part 2" course a few years ago. They don't really give you much useful advise on temperature control though and using a few simple techniques and the right fuel you can regulate the Weber temperature quite finely.
Talk to Steve (Smokin Monkey) about self build Tandors - you can share war stories . Steve brought one of his to last years meet and it was a great success.
If you have any questions please do not hesitate to ask and please do not be afraid to share your experience with other where you think it will help. We do like photos on here so don't forget to include them regularly.