Thanks - Odin already has fibafirst but they have the same reaction as pellets if he has too many, and they still have ingredients I'd rather not feed too much. I've got a 2kg box of Rosewood coming today (only a fiver or so on Amazon) to try, I was thinking that it is pretty much a concentrated version of his normal diet, so I could maybe get more of the same in with less effort on his part, then he still has plenty of space for eating normally too? He will very easily just not eat his normal diet if he has too many concentrated things which has a knock on effect on his teeth and gut very quickly.
Rosewood says (somewhere!) that is is suitable for all ages, but yes, I am a bit wary of that especially being a giant. Hence thinking of trying him with the Bunny Nature Junior - probably a better quality too, the German horse and rabbit foods I've had in the past are generally excellent quality in comparison to ours.
I also found that Agrobs do rabbit pellets - I love their horse feeds for the Fell ponies, and have used the grass pellets for the big buns in the past to have something to put in their enrichment toys, and the fibre content is incredible, 30% or something similar. Not sure if I can get it in the UK but I'm going to look today. I'll compare the analysis with the horse feed too because it may well be the same thing in a smaller bag.
I was thinking maybe Luggage would benefit from some Alfalfa too while he's growing? I wonder if that might be worth a try for Odin too?
The other thing with the fibafirst is that I'd really like some pelleted something to use in toys for Luggage while he is still isolated, so that we can keep him better entertained. That's the main reason I had pellets for the big guys initially too.