Once again, welcome to the BAA, and I hope you find your membership rewarding. I’m not a variable star observer (although I do try and estimate the brightness of comets and the brighter supernovae). My particular interest is deep-sky and I was Director of the Section until a couple of years ago. Of course this is not a good time of the year to start deep-sky observing – particularly when you live as far as north as you do, but in a month or so you will have some dark sky to enjoy. Most deep-sky observers want bigger and bigger telescopes to play with and I must admit to going partly down that route myself, but there is a lot that can be enjoyed in small telescopes or even binoculars. Some open clusters are too large to fit comfortably in a telescope view but are ideal for binoculars with their wider field. Also some objects can be visible in binoculars but not in telescopes. The local group spiral galaxy M33 in Triangulum is easy in 10×50 binoculars but very difficult, because of its low surface brightness, in even quite large telesccopes.
Very few people are now doing deep sky observing in small telescopes, so you could really have something to offer (but do expect to get bitten by aperture fever at some point!). If you live in a dark sky area most of the Messier objects should be visible in your telescope and that would make an interesting personal project. And one that I’m sure the Section would be interested in.
If you want to start out in deep-sky observing one book I can thoroughly recommend is Deep Sky Observer’s Guide published by Philip’s. If you are buying secondhand make sure you get the revised edition published in 2013. The author is Neil Bone. Neil was the BAA Meteor Section Director and unfortunately died from cancer a few years ago.
Most amateurs have a general interest in all aspects of astronomy but also find that there is one particular area that interests them the most. If that turns out to be the deep sky then I hope you find it as rewarding as I have.
Clear Skies, Stewart