If you haven't flown all winter you need to go up with an instructor - very simple. 50 hours over the summer and a few months lay-off probably means you're out of practice. On the other hand, last year I kept more or less current on f/w aircraft while mainly flying helicopters, by circuit bashing for about half an hour every 3 weeks or so; I wasn't brilliant but I was safe. And that wasn't even 12 hours in a year (it was by the time I'd done the Dawn to Dusk and flown to Ireland though). It comes down to common sense and knowing your own limitations. Unfortunately you can't teach those.