@TheBigMacDougal we are going to try the implant with FawkesPup.
He's also a confident, happy-go-lucky kinda boy so no worries on the temperament front but vet said leave it as late as is feasible. He's fine to have it now, equally if he's not causing any issues then leave it and allow the hormones to do their job. So I will.
He's also a teenage twat. Luckily for him he's also a poppet and a total cuddle monster.