It seems as though the Merrida/CRC Marathon series has been resuscitated as ‘MTB Marathon Series 2014’ and they’ve got a round at Drumlanrig.
Distances of 25-100km, more info here: http://www.mtb-marathon.co.uk/events/3rd-august-2014-drumlanrig-castle-scottish-borders.html
Even better, the picture on the website shows sun, so that’s legally binding I imagine.
Anyone else fancy it?