I've decided to try taking sugar and cereals out of his diet, since the skin lumps came back and he got very grouchy immediately after being fed (or possibly skin sensitive - didn't like being touched after he'd eaten, fine the rest of the time). So with some help from the barefoot community, the Feet First book and the very helpful advisors at Simple System, we've moved over to a non-molassed beet (currently Speedibeet, though I'll be trying to get Purabeet when I can, it's cheaper), Greengold (a non-molassed lucerne) and a supplement called Total Eclipse (linseed, magnesium oxide, brewers' yeast and seaweed).
We're still in the process of switching, he has a trickle of Leisure Mix still which is being reduced daily and he'll be off it completely by about Wednesday. A bit too early to report on results, but he does seem less grumpy and he's licking his skip clean every meal which is a relief - a lot of horses refuse to touch non-sugared stuff if they've been used to the sweetness. I think once the TE has run out I'll buy the ingredients and mix my own - I suspect that with being coastal the iodine content of the grazing will be pretty high and I shouldn't need to supplement seaweed. Going to get a forage analysis done in the spring.
His weight touched the 510kg band 10 days ago, but he was back in the 504kg band this morning. With the way the weather's going I suspect he'll start to lose it again now, if it gets too quick then I'll up the quantities of beet and lucerne and possibly add in something like Blue Bag grass nuts, though he's always got hay available.
As far as the exercise plan goes we did really well the first week, but this week has been horrible weather-wise - lots of rain and some strong winds and there's just no point in trying to walk him in hand in that, he spins round to turn his bum to the weather and refuses to move. I was going to take him out this afternoon, but fell asleep on the sofa - I seem to be constantly knackered at the moment :o(
There's a UKNHCP-qualified trimmer coming next Sunday to do his feet instead of the normal farrier. It'll be interesting to hear what he has to say. I suspect it'll be toes too long and heels slightly under-run and more roadwork required.