Kimberworth has a very nice 4X track in sheffield which is good for mountain bikes and BMX. We rode it on MTB and it was a really nice track. The only downside to this place is the wind. It is built on an open field on top of a big hill and the wind can really catch a good rider out if it gets you from the side.
It is made from a very hard sandy gravel which means you can ride in any weather and there are two big berms …

These trails are located in West Yorkshire and are a reasonable size. They could do with a bit of TLC before summer to make them even better. These are suitable for BMX or Mountain Bike. The trails are fairly steep so not for the faint hearted.
Heres the pics: