Hi Teresa
About 4 years ago we were in the same situation as you. The good news is we now have 2 fields comprising 24 acres, 1 of which we rent to a farmer. So we are working on one 12 acre field.
The ads for land just didn't seem to work. Each time we saw something interesting we would put in an offer about 10% over the asking price and get nowhere.
We found a company called Woodlands, see:-
http://www.woodlands.co.uk/buying-a-wood/east-anglia/who buy a large area of woods and scrub, divide it into plots (typically 5 acres) and sell them off. The price is fixed and you can buy one or several plots (if you are quick). This might be what you are after. The drawback is that the plots are priced for prime agricultural land but are often fairly low value scrub. Also, you don't know who will be your neighbour. I leave you to speculate what they might be like!
Anyway, what worked for us?
We noticed that one or two estate agents were active selling land in the area we were interested in. We approached one and paid several hundred pounds for them to act as land agents on our behalf. They advertised and got some offers of land privately so we had first pickings. The agent advised on what to bid. We got our land at what seemed like a high price at the time but the asking price for similar land has gone up since so it's been a reasonable investment.
We may sell our second field if we need the cash or realise we have enough with one 12 acre field. It's our choice.
Completing the purchase involved a solicitor who did the usual (house purchase) checks on ownership, boundaries etc. This took several weeks but went smoothly.
I hope you find what you are after.
Good luck
NN