Before I went for a official meter I purchased a basic dial water meter from BES. From memory it cost around £25 and I fitted myself under the stairs after the incoming stop c*ck. I only removed and scrapped it around 3 months ago when I had to make some alterations to the pipe-work. The cheap meter I purchased was for 15mm pipes but found no significant difference in flow when fitting it to my 22mm incoming pipes (via reducers).
It's probably not worth going to the effort of automatic logging as you are only after a yearly usage, maybe split in quarters to mirror billing periods. Logging more frequently may however enable you to detect leaks/dripping taps etc.
My water usage is fairly flat over the year. I tend to have more baths (as opposed to showers) in the winter and water garden plants in the summer.