Some of the details don't ring true but this sounds like McAlps leading a stream back to Laarbruch trying to make it before the bar closed when he was overtaken by an aircraft above him with a blue pulsing light. Dutch Mil said they couldn't see it.
I was sitting in my quarter in Goch at the time, and, within ten minutes of the incident, the whole town was shaken by a sonic boom. We had had a similar boom some weeks before and Wildenrath had gone on BFBS to apologise for an over-enthusiastic F4 pilot. My mate in ATC told me that Wildenrath had not been flying at the time of the first boom.
I seem to recall that Nick Pope considers this one of the two best UFO cases with UK involvement, along with the overflight of Shawbury/Cosford.