A Crucial Win

Here's a game which I won recently at the Durham Chess Congress. I scored 3/5 in my category: not too bad for my first tournament, but I lost at least one game which I should have won. I needed to win both my games on the last day to get the £50 grading prize, which I managed. The first of them is shown below. I may post the second one later but it required less effort due to several obvious blunders by my opponent. This one I was quite pleased with, however.

I have not included ratings as they were given as ECF grades, which I am not too familiar with. Any comments/further analysis would be welcome.