Not Shrewsbury but I've had something similar out near the Trough of Bowland about three years back. Big black cat, way too large to be a domestic gone feral, moving along the treeline at dusk. The way it moved is what got me - that low, deliberate stride. Nothing like a dog moves.
People round here dismiss it every time. "Oh it's just a big moggy." No mate, it isn't. A German Shepherd sized animal moving like a predator through a field is not somebody's escaped house cat.
Theres a reasonable theory that big cats have been quietly self-sustaining in rural Britain since the Dangerous Wild Animals Act in 77 forced owners to release them. Enough sightings across enough decades in enough separate locations to suggest theres actually something to it.
Anyone got footage from the Shrewsbury sighting or is it all eyewitness at this point?