Good luck - I can tell your looking forward to a good plot.

I'll second punting perenial ryegrass. The only reason I would ever plant a perennial ryegrass would be plant an area that I didn't expect deer to feed, and that I mowed once per year. The grass can offer seed and cover for birds, mice and even deer fawns - but deer will very seldom eat it. Farmers sometimes mix it with a clover or alfalfa to add ruffage to the cow's diet. Deer just "skip it" in their diet.

I'm all for a mix, but keep in mind you will want to mow a couple times - look at an annual cereal grain like rye or oats in the mix - but concentrate on the clover for deer. I cannot comment on chuffa - never planted it.