I just double checked and planes following each other are typically separated by 1,000 feet in the UK. But 2-3 minutes is roughly the minimum time separation for larger planes.Planes two minutes apart never climb to same height on same route.
You can’t judge plane height from ground , only a dumb f*ck would think they can .
So one or the other could be true, they could be at the same altitude but far further apart, or they were fairly close and different altitudes.
