RateTheRef

Could be Jim Whalley of Southport perhaps?

19.09.1973   Fortuna Düsseldorf - Nĉstved IF   1:0
Ken Burns -  James E. Bent (Hemel Hempstead, Hertfordshire) and Alan Bradley (Accrington, Lancashire).
24.10.1973   OGC Nice - Fenerbahçe   4:0   
Ken Burns - Robert "Bob" N. Perkin (Littleworth, Stafford, Staffordshire) and Frederick Brian "Brian" Handy (Brownhills, Walsall, Staffordshire)
27.11.1973   Dinamo Kiev   - VfB Stuttgart   2:0   
Ken Burns - Roy Swallow (Sheffield, Yorkshire) and Alexander "Alex" R. Lees (Street, Somerset)
06.03.1974   Ruch Chorzów - Feyenoord   1:1
Ken Burns - ? Lin and ? Volley (note data from the Polish press, the names are probably distorted).
Possibly Dennis A.J. Ling (Witham, Essex) and James "Jim" Whalley (Southport, Lancashire)

B.A. Voizey of Yeovil was on linea already involved in the UEFA Cup match 03-10-1973 RWD Molenbeek - Espanyol (referee David W. Smith).

B.A. Voizey of Yeovil was on linea already involved in the UEFA Cup match 03-10-1973 RWD Molenbeek - Espanyol (referee David W. Smith).

After further thought I wonder if the earlier suggestions of D.A.J. Ling and Jim Whalley may be more likely. Ling was also in his last season as a FL linesman (I originally thought he'd served longer) so he would be a likely fit for "Lin". That would mean the other linesman would be a relatively new FL referee. While Voizey seems a more likely explanation of "Volley" Whalley is also a possibility and he was a relatively new FL ref. While Voizey making a second European appearance that season can't be ruled out - indeed it could have been a good move to use the same linesman again - it would seem unlikely given how the English appointments were done. Sometimes a referee profile would mention that he had done a specific European game but it's hard to test that for Jim Whalley as his League career ended soon afterwards.