With a liberal coating of South Wexford mud from the beet, they weathered to a greyish brown colour, to such an extent that the original brown (and yes, that's way too red) was completely obscured. So much so, that operating them in a pristine state would be akin to a "wrong livery", same as an all silver A or C class loco, or tin van!
So the solution is to very heavily weather them, and all will look good.