Mind you, I once received a penalty notice for driving through a red light in Hull at 9.30 on a Thursday morning. Not only have I never been to Hull in my life, I could also prove that I had been standing in front of a class of 30 kids in Hertfordshire at the time in question, with said car in the school carpark. They dropped the charge without fuss. This was 25 years ago, mind, so possibly their camera footage was less exact than nowadays and read the number plate wrongly.
I had a speeding fine from the other end of the country - I'd never been there and my car was in the car park at work at the time of the summons. It was a registration plate scam - same registration, completely different make and model. It was up to me to prove it wasn't me rather than them to prove it was, and it was made very clear if I didn't provide proof I'd be liable. It was unnerving.
Similar happened to my Mum in the early 90s. She had a fiesta xr2 and the police phoned one night because it'd been involved in some sort of crime, they wanted to know if it had been stolen. Happily it was locked up in the garage and the plates had been cloned. I imagine it's a lot harder to do now given the ID etc that has to be provided to get number plates.
Back to the OP, it's been a long time since I've had any involvement in motoring law but I'd think if you admit to driving you might be able to take a fixed penalty of 3pp and a modest fine. Prosecutors were often happy with either the fail to provide drivers details or the speeding itself. I'd notify dvla of your change of address for your licence and registration document now though.