Ahhhh! OK, Nelson, this isn't a "Brown Van" at all - I misunderstood you. I thought you meant one like the recently restored one at Whitehead, or the trio at the DCDR. Those ones relate to the info I gave you.
The above is a standard NCC goods van, which I would guess dates from mid-1920s to mid-1940s build. A van like this would have been all grey (standard LMS wagon grey - sloghtly darker than GNR), if unpiped; all bauxite if piped for attachment to passenger trains.
I am unaware of roof colour, unfortunately, but since this is obviously of fundamental importance I will endeavour to find out. I suspect brown too, but I'd prefer to check. Chassis, drawgear, etc would be brown.
This one, like most, would have remained as it was under UTA ownership, in all likelihood never being fully repainted, but just with lettering changed by painting a "patch" over the lettered bit, and replacing with UTA markings and numbers.
JB