Liam,
I use Sykes quite regularly.
You can go to the yard to collect your timber, but they don't normally let you select it.
If you speak to the right person you can safely leave it with them to select decent stuff. (They don't sell rubbish as a rule anyhow.)
They do like a substantial order, but you won't need to order a lorry load, and they will deal with the hobbyist as well as the professionals.
If you are unsure what species to buy, once they know what you want the timber for, they will make suggestions and offer what they think will suit you. You make the decision of course, but I have never had a disappointment from them. They don't stock a massive range of English Timber, but they do have some English Oak as far as I recall. They also stock Genuine Mahogany.
I live about 25 miles from them and they delivered free to my door. The stuff I have from them is always good, at mid to high market prices; dependent on species. I don't know your full requirements, but I recommend them 100%.
As for selection, you could always ask if you could be there when they pull your timber. Their policy might have changed.
If I recall correctly, ask for Ben, when you phone. he's never made a bad selection for me.
I have NO interests in the firm itself, they don't know me other than as a customer, but as said, I rarely go elsewhere; (Maybe Whitmores for my quarter-sawn oak... Soon!
I phoned Whitmores recently, and they told me as long as I make an appointment, I could go to the yard, and make my selection with one of their workforce. That was as good an arrangement as I need!
There is also Harry Adkins near Corby Glen, Lincs, who are quite good, for air-dried English timbers. As far as I know they are still operating, (Google Earth tells me so at least!)
HTH