At first, it seemed that it would only give the right frequency above 14MHz! Anything below becoming progressively more inaccurate, until around 5MHz where it was all over the place!
After a nice hot bath, and a bit of a think, I went back and gave the frequency counter a bit of a kick! I realised it was the counter that was playing up, not the DDS module! A bit of fiddling with the input ports, the range switch and the trigger level and I proved the output of the DDS on all the controllers 'standard' frequencies, which are all within the amateur bands, this including 500kHz and 137kHz!
I just need to add the encoder now and some real buttons!