Learn how to defend legkicks, learn some takedown defence, and never try to engage a jiu-jitsu fighter on the ground, do anything to avoid hitting the floor with him.
Start Muay Thai first then add your ground game. The stand up grappling of MT will give you a good intro and experience of different levels of attack. Add a good ground style in due course and work on linking the two. The puzzle is different for everyone but our boxers cross train quite a bit with the Muay Thai and MMA fighters and this is the approach that gets good results in our experience.
Maybe think about a weight training programme to increase your core strength. By increasing the strength of your muscles in your back, abs, and plevis you'll be sacrificing a bit of the flexibility in that area required to be a boxer. But it will help with your clinch and grappling. It's very simple to say 'Learn take down defence' but core strength is relatively under appreciate aspect of a MMA fighters training and is the reason wrestlers hold a huge advantage in take down offence and defence. It's also the reason why MMA fighters look sloppy when punching compared to boxers, as they dont quite have the same flexibility in the hips and throw arm punches A boxer obviously have a great base when it comes to striking. But you'll have to make adjustments in your stance, as side on utilised by boxers makes it easier for someone to take you down as most of the weight is on the back foot of a side on stance. If you stand stand square on and spread the weight across the shoulders and keep the center of gravity in the middle, again you will be sacrificing some boxing technique for a great ability to defend a takedown
Defensive wrestling, learn how to get up after being taken down, learn BJJ. Learn Muay Thai, this is important pure boxing can be offset if you dont mix it up a bit.
Only as a hobby mate- I absolutely love it but might have a couple if I get good enough. Can anyone recommend me some good guys to watch. Like Paul Daley as he is obviously mainly a striker but i'm a complete noob with regards to the sport. I don't even like watching it that much!!
The less important things to learn would be offensive wrestling (as presumably you would want to keep it standing) and fancy Jiu Jitsu because it is hard to pull off and takes a very long time to become good at. Another important thing is what Stoo said, you need a very different type of strength to be a good grappler.