Where to get flex shaft cable for a Pro rotary trim cutter?

I have borrowed a Pro rotary trim cutter model number CLM701WHT6 & the cable in the flex shaft has snapped. It is a B&Q own brand & has been discontinued. I want to know either where I can get a replacement cable from or whether a flex shaft from a dremel will fit it? Have already tried Pro's helpline & they're about as much use as a chocolate fire guard!