Good to hear you are progressing with the allotment, if the council will rotavate the patch, let them do it! My allotment was just a very rough nettle-ridden edge of a field, we rotavated it twice and then dug it over several times to get out all the roots, this certainly pays off, but it's hard work. Test you soil (a kit is cheap and easy to use) Enrich the soil during the autumn, farmyard manure is best, but things like Growmore pellets are good.

Invest in a good book----
The Vegetable Expert-Dr D G Henderson is a good book on the subject--
Another that I use a lot is "Your Kitchen Garden" by George Seddon, they may be available in your library.

I have tried many catalogues and always come back to --
MARSHALL & CO LTD
FREEPOST
WISBECH
CAMBRIDGESHIRE
Look them up on Googgle, you can send for a catalogue, get newsletters etc etc. Send for some autumn planting onions, garlic and shallots and plant when you can.

I have tried most crops and now know what my plot grows best and concentrate on them.
Most of all have fun!