How are you getting on @Tickytocky?
I agree with pretty much everything said above!
So many people throw away marks at prelim, eg are your circles accurate, or a big egg shaped? Are your transitions accurate, is he/she listening to you so that you change pace exactly where you mean to/first ask?
I used to compete my little 14.2 coloured cob at UA and dabbled at quest/BD. He actually did very well, a lot of which was because he was reliable/unflappable- eg when the beautiful moving and v impressive looking warmbloods lost their marbles at the flower pots/random shadow in an indoor arena. So we were able to make every mark for accuracy/rhythm count.
I would also third/fourth the comments about moving up a level when you feel he’s going nicely consistently. It is a regret of mine. We had just started doing some novice classes when he injured himself. With hindsight I wish I’d loosened up a bit. He was consistently scoring 70ish and his mediums were pretty crap so I wanted to wait until they were very clear and… well better! But actually they are just one or two movements in a whole test!
When I was struggling managing a toddler and horse, our instructor rode once per week over one winter. It was brilliant and absolutely money well spent. I’m a complete amateur and it really helped him, with me it was a bit ‘blind leading the blind’.
The other thing to touch upon, as was mentioned above, is fitness. Many cobs (mine included!!), are very chilled out, and not naturally very foreword going… the fitter they are the easier they find it and therefore the more willing they are. I started doing a lot of fitness work and got into endurance, and it really helped. I used Equilab to track how much w/t/c I did in every session and it was enlightening! Most people hack and spend 98% of it in walk. Really use your hacking. Ask him to march out. Use lots of transitions up and down the paces. On wider tracks leg yield side to side. Also mix it up to keep it interesting so fast hacks/fun rides/a bit of jumping. Don’t just go in the school and drill them as they switch off.
Good luck and let us know how it goes.