Also flown off the coast north of Flamborough Head.
NOTAM put out for the area and Canberra towing the banner established on its pattern. One of the fighters performed a surface sweep to ensure no vessels in the area and when the area area confirmed clear it proceeded as normal.
Didn’t stop VFR traffic regularly penetrating the area and having to call stop on a frequent basis - but I can’t remember an APC not achieving its NATO qualification requirement - though that was hushed up as much as possible….