Yes I know, someone local used to cross their pure Swales with Cheviot and sell big store lambs rather than mule gimmers. I personally like pure breeding trying to improve certain parts of breeds, it’s just down to preferenceI do have 1 chev tup to see what I think. The cross ewe is ok but think I'm preferring 1/4 chev blood in the flock. The beauty is I'm not locked into any breed or type, just use the tups I fancy and can take my ewes in any direction.. but once I breed or find a tup I like I tend to use him extensively.
You'd be disappointed with the lambing % of a Cheviot compared to your Swale