Well I ordered a 3m cable and that wasn't long enough so I ordered a 10 metre cable and that has now given me enough length in order to get a proper signal from our studios.For information I now have the galleon serial clock running on extension cables totalling 13 metres and it still works fine many because it is powered at the unit itself. I ordered the cables from www.cabling4less.co.uk and for the 10 metre extension cable it was £10.43 including delivery.
Hope that helps those in a similar situation