Hi Ruairidh. As a senior officer in the grammar police, I assure we only correct native speakers - the non-natives are generally too familiar with our grammar to commit howlers. As a Scot, you qualify as a native speaker - but with a Gaelic spelling to your name, we'll give you the benefit of the doubt and be gentle with you!
New referees generally struggle, in my experience, with four things:
a) processing what they see quickly enough to react by blowing (or not blowing) the whistle
b) positioning at breakdowns or set pieces to enable them to get to the next breakdown in time to see the first offence
c) fitness
d) communication
Of these, only d) is probably not something you can work on in the off-season. I would suggest the following:
a) the primary problem is the tackle, where it becomes a ruck. Here, you need to visualise what you expect to see at each point. At what point does Law 15 give way to law 16? And what are the precise requirements of each of those laws?
b) If you played, would you be a forward or a back? Positioning is different for a nippy winger-type than for a heavily-muscled (or just heavy!) front-row type. The slower or less fit referee needs to anticipate where the next breakdown will occur, and give himself a head start on getting there. The trouble is, he's then in the way of the pass between #9 and #10, or interfering with the defensive line. That's a tough trick to manage, and requires experience. The only short-cut is to seek advice from other experienced refs. Feel free to post here. The whippet-type ref also needs to anticipate where the next breakdown will occur, but he has the luxury of being able to position himself on the far side of the ruck, knowing he'll be able to chase around and still arrive early at the breakdown.
c) Consider refereeing touch rugby, which is fantastic aerobic activity and is remunerated. Otherwise, just avoid watching the alleged sport of cricket - or (come to think of it) any other summer sport. Stay active, work hard on your fitness. Some refs ref to get fit, and they rarely get anywhere. The refs who get fit to ref are the ones that progress.
d) Don't be tempted to watch replays of Scotland getting stuffed to see how the elite boys deal with communication. They have ARs, TMOs, big screens and pro players to assist them. Consequently, they communicate very differently than the grass roots ref. I'd leave this for next season, and ask to be assessed as early as possible so you can get tips from your assessor.
Have fun with the reffing, but Dickie E's advice is also sound - take a break. Do follow this site, and do post questions regarding in-goal, which catches out almost every new ref.