Here you go Deano,
Get your millimetre ruler out on this one to realise the 05/23 tarmac length Perranporth already has and what extension, between the 05 threshold and the disused perimiter track is feasible and, as I suggested, I think there's room for a tad of an extension of the 23 threshold end also.
http://www.ead.eurocontrol.int/eadba...2013-04-04.pdf