That’s odd
I was running in those road relays way back then.
First of all - one could take road relay distances with a pinch of salt.
I presumably ran the City of London Police 3 mile road relay leg in under 13 minutes a couple of years before Ron Clarke did it at the White City!
My memory of running in the same relays as Coe during his brief period running relays for Haringey was that we were all very much surprised how (comparatively) slow Coe was in these races and we concluded that he would never had made it at the 5000.
I can’t recall him ever running the fastest leg.
Look up an old TVH road relay result at that time and see just a surprising list of those who ran faster than Coe.