My advice is just to suck it up and get your knees used to it. Knee pads really arent that great there actually sort of a nuisence because there itchy and they move around on your knees. Your gonna get bruises and cuts its just part of being involved in a contact sport.
Order them off any high school wrestling web site or wrestling magazine. They tend to be kind of big for my liking but I personally got mine at Dicks sporting goods, but I see your from Manchester which I'm assuming England so you wouldn't have a Dicks so probably just order them offline.
Kamikaze is now 5-0. Watch his most recent fight here.