4 down - TV presenter has one opponent - (4) - A-T-. ANTI? I dont get it.
14 down - sobriquet of labour leader embracing relationship with gusto - (3-7) ---B-O---D.
-15 across - cosequence concerned with striking - (12) -E---C-S-I-N.
25 across - I upset goodliest visionary - (10) ---O-O-I-T.
Many thanks bulliver and sedge47. Sorry for the delay in replying - Windows 7 very helpfully decided to reconfigure itself so I had to start my reply all over again. Not long now before my PC finds itself with a star-shaped hole in its screen!