New allotment

Hi everyone.  I have just taken over an allotment and have no experience.  It is in good condition and I dug it over and have just planted leeks, spring onion, cabbages and salad kindly donated by my neigbours.  In my greenhouse I have tomato plants, cucumber plants, , chilli and pepper plants.  I have also done trays of herb seeds, parsnip seeds and aubergine seeds (but think it might be too late for them).
I am struggling to find anything else to plant outside as there is nothing in my local shops and I keep being told it is the "wrong time of year."  There must be something!
Can anyone give me some advice on fruit/veg I can put in now and also point me in the direction of a gardener's diary so I will know how to look ahead and plant ahead.
Many thanks.

Thank you.