We saw 40129 a little earlier approaching Caerleon, see....
https://www.ontheupfast.com/p/21936chg/30022609720/x40129-severn-tunnel-junction-freight Having deposited its oil tankers it now sits with its engines off at Severn Tunnel Junction awaiting its return to the north-west, once away from their home depots and regions it was never long until they returned again. 25274 sits just in front of the Class 40 with a Class 47 and 37 in the background. Of all the locomotives seen here it is the Class 37s that were always synonymous with South Wales throughout the first-generation diesel years.