Dear Kev,
I just wanted to add my voice to the chorus of encouragement. I share a plot in Bedford with a friend, and between us, we remain quite clueless. The first thing we had to get straight was our mindset. We were there for fun, so if things weren't quite right, it didn't matter.
Having said that, we have been late every year (this will be our third summer). We were lucky to have very kind neighbours. Nonetheless, in the first year, we didn't plant things till May I think. It didn't help that we have solid clay that hadn't been cultivated, apparently, for 10 years. Everyone passing would comment that we'd left it rather late. Later on in the summer when we were harvesting food, we got a chorus of, "haven't you done well". So don't worry, you have time, even in gorgeous County Durham (I spent four lovely years in Durham).
As I mentioned, we didn't know the first thing about gardening and were reading a lot, but didn't always remember everything. So when we were given advice, it sometimes confused us further. I do remember feeling somewhat overwhelmed at one stage, until I reminded myself it was for fun.
Having said that, I would greatly encourage you to draw up a plan of your plot, and then decide on a small section to deal with this year. And please cover the rest. I say this from experience. When we first took the plot over, we had it rotovated and then didn't cover it, thinking we'd get round to it, but got sidetracked by other things on the plot. The combination of chopping up the weeds when rotovating and leaving the ground exposed meant we had a fine harvest of weeds to contend with, which added unnecessary work. We used carpet because I was renovating my floor, but I would agree with the other posters to avoid it if possible. Eventually we bought some damp proof membrane from Wickes for £30 and put it down. Its worked a treat because its thick enough.
Planting potatoes was hard digging, but real fun to harvest. And they help to improve the soil. Similarly, shallots are grand because you plant one but get lots. There are quicker growing veg to put in too. Because of our clay soil, we used two drawers from the tip to build a carrot box. Mixed two growbags with one of sand (I think) and the carrots worked a treat. Just be warned they do take an age to mature, for some reason I thought they would be quick veg.
Good luck, and remember its also meant to be fun.
Undala