There are a few around the Silverstone area, Silverstone is decent has a good club house, they have two pro's who both teach a driving range and good 18 hole course. Very close is Whittlebury hall which is also nice with great off course facilities, it's not as expensive as it sounds has a good bar and the added bonus of a two tier driving range.
There is a good course called Edgehill just outside Banbury and another outside Bicester. They all have pro's and driving ranges they are the ones I use as they are close to me there are loads about though.
Don't know what DIN, but easy to find out from your PTI or admin staff. I did the course a few years ago. There are 3 levels - Beginners, Medium and Advanced. Have to pay about £100 out of your own pocket, and this allows you the tuition plus use of the facilities all day i.e course and unlimited balls on the driving range. Tuition is by 2 guys (civvie - no PTIs in sight!)- one was a pro who taught the short game, and an amateur that taught the long game. Tuition is for half the day and then you are free to do your own practicing, game or go home.
I did the beginners course and it was really worth the value, as it allows you to learn the skills without having to undo lots of bad habits. Only problem is finding the time to put into practise what you learn. Golf is a game that needs lots of practice. One of the better adv trg courses!