What a wonderful signature tune this is...

[billfromnorthwales@...]

On the end of an old tape I found the end of an show but I can't date it
 

 http://www.peel.mooo.com/peelgroup/BillfromNorthWales/01%20John%20Peel/197x-xx-xx%20John%20Peel%20BBC%20Radio%201.mp3 http://www.peel.mooo.com/peelgroup/BillfromNorthWales/01%20John%20Peel/197x-xx-xx%20John%20Peel%20BBC%20Radio%201.mp3

 

 

 Go to 4:28
 

 Late 1975 perhaps? 
 

 Sounds like he recently started using Grinderwitch as the signature tune

 

 I thought it may be 28th October 1975 but nothing seems to fit (a Caravan session followed by a 37 minute "rather special Mouldy oldie" the next day..
Not a play of  Ommadawn by Mike Oldfield)

 

 Any ideas?