A quich search of my Airborne Forces Experimental Establishment records show that the following reports were written.
AFEE/T2 dated 19/10/42 Wellington 1c as tug for Hotspurs
AFEE/T5 dated 30/12/42 Wellington III X3286 towing Horsa. Engine cooling tests.
AFEE/T21 dated 11/11/43 Wellington X HE731 towing a Hadrian.
AFEE/T22 dated 16/11/43 Wellington X towing a Horsa.
AFEE/T24 dated 19/11/43 Wellington III X3286 towing a Hadrian

and just to further muddy the waters how about this one.

AFEE/T27 dated 13/12/43 Warwick I BV230 towing a Hadrian

And I take it from the lack of response to my request last year that no one has any photos of Spitfires towing Hotspurs.