I think a discussion from some time ago indicated that the laws do not allow for you to wear any form of camera. The only legal option from a LotG perspective would be to set up a camera on a tripod at the side of the pitch, which would be fully legal to do on public land (on private land you might need the permission of the land owner). But with this approach you're only ever going to get a wide-angle long-shot of most of your decisions, and the camera is susceptible to being hit by a ball (or stolen!). Perhaps have a friend that comes along and records you on some of your games?