These: www.woofwear.com/for-riders/footwear/long-yard-boot-2017_33.html. Would you wear them to ride when using the caged stirrup irons? The irons are a bit like these, but much sturdier: www.ridingwarehouse.com/Korsteel_Polymer_Stirrup_Toe_Cages_Pair/descpage-KPSTC.html
I wouldn't normally consider it, but it seems to me that the stirrup irons make a difference to the normal rules. (Indeed, I've seen kids riding in trainers and wellies without any objection from the riding school.)