Brevet cards (and routesheets) work. You just have to make sure they don't get wet (the organisers provide adequate wallets). I wasn't inputted on the tracker at the penultimate LEL 2013 control, but my card showed I was there. This year I was clocking out at a control and the volunteer said I'd only been there 40 mins or so, looking at the computer, when I'd been there a few hours. My Garmin drained and wouldn't recharge from the dynamo in the cold at the weekend, but the paper routesheet was fine. Don't businesses still have paper copies?
I received an envelope from Norwich today. Oh what joy when I opened it! Thanks Fidgetbuzz et al ☺