[cloddopper]

I might be wrong but I think most wild hazel nuts are actually filberts which are a lot smaller than the Spanish hazel nut .  If you do find a decent size nut  see how many you can get off the same plant .   Come Nov  pop them in a big plant pot an inch and a half deep ( 5 x  the biggest dia of the seed )  & cover it with some mesh to keep the squirrels out & water well .   Put them in a shaded position that gets a bit of wintersun .  By May you should start to see the new nut  tree's emerging .

Pot grow them to about a foot tall   give them a few  BabyBio feeds in spring & late (ish ) summer , then plant them out in the early November when the leaves have fallen .
 Planting them through a hole cut in a couple of sheets of thick weighted down cardboard helps keep the weeds at bay & stops them drying out till they are strong enough rooted to crack on by themselves .

[pgkevet]

There's certainly several types of identifiably different hazelnuts here. Reading suggests many may be natural hybrids. The largest nuts are from several bushes in one hedgerow albeit smaller nut variety bushes there too.
I shan't bother with planting any new ones cos I've got more than enough and unlikely I'd be around for the benefit although i did put in several sweet chestnut from supermarket nuts a few years ago and may just be around for the product. My walnuts and money puzzles will have to do as a legacy 'cos the odds are i won't be around for those either.
I might put some more cherries and a plum or two in but with 13 cherry trees so far the birds still haven't left me any.
The largest nuts may have been cross pollinated with the smaller varieties so it'd still be a lottery. I did try and germinate supermarket nuts with the chestnuts with dismal failure on the hazel and almonds and walnuts. I guess they'd been sterilised.