I've rented off the Environment Agency for years - both yearly grazing and FBT.
The agreements are absolutely straightforward - just read it through and make sure it's what you want. Things to look out for are any dates when the livestock have to be off, and who is responsible for fences. It's worth checking state of fencing first as you don't want to repairing a lot on a 2 year tenancy. You might need to get written permission for applying fertiliser or herbicide, but if so it'll all be mentioned. You shouldn't need a solicitor.