This  country combo was just observed on Ebay. It is a US William Booth cachet (Fleetwood) cachet with UK stamps postmarked on first day of issue for the stamp set (09.08.1965) – cancelled in Preston. Likely a connoisseur cachet – only a few similar have been observed on various web sites, i. e., with UK stamps on US covers. Sold on Ebay April 2020 for £43 (reference cover – not in my collection).