Hi Alex and welcome to the forum
There are a few of us from the UK who chat here and so it is always great to see a new face :). Where in the UK are you from?
Which type of smoker have you bought? There are a lot of different types and they all have slightly different "personalities". What are you looking to cook? Will you be mainly grilling (a lot of people do, even on a smoker) or are you looking to cook things like pulled pork, ribs, brisket etc.? Maybe you will also be using it to hot roast things like chicken, joint roasts etc.
When roasting or cooking low-and-slow the first thing you need to master is the temperature control with your particular smoker. Just like cooking in the oven, for best results you need to be able to bring it to a specific temperature range and be able to hold it there for several hours. The method of doing this will depend on the type of smoker that you have bought. Also some smokers out-of-the-box require some simple "mods" to help you cook with them efficiently. These are usually quite simple and are to do with sealing air leaks.
My advice would be to start with some inexpensive and forgiving meats while you are mastering the temperature control. Sausages, a small pork joint or maybe a beer can chicken are good to learn with and if they go horribly wrong then the dog will still enjoy them ;). These can be cooked at higher temperatures (~160-180 C), which are easier temperatures to maintain and are only required for an hour or two. Then you can progress onto the low-and-slow meats like pork ribs, pulled pork, brisket etc. which require temperatures of ~110 C to be maintained for 5-10 hours - depending on the meat.
One accessory you will really want to get for roasting/smoking meat is a dual probe digital thermometer (search for Maverick/Readycheck ET-732/733 or Inkbird) as these will give you an accurate temperature measurement of both the cooking grate and the centre of the meat that is being cooked. Once you start you will realise the importance of cooking by temperature. If the smoker you are getting has a lid thermometer then it is best ignored. Most integrated thermometers are too inaccurate to rely on.
If you are looking for inspiration and advice then you may like to come along to the Smokers Weekend that is being held at Billing Aquadrome in July (20th-22nd). It is a good family friendly meet where BBQ/Smoker enthusiasts meet in a non-competitive environment to share some great BBQ and a few beers. All levels of experience are encouraged and you will get a lot of good ideas from others there and you can also benefit from their experience. More details can be found here
http://www.woodsmokeforum.uk/topic/...and-bbq-weekend-billing-aquadrome-20-22-july/
Cheers, Wade