Just noticed this thread so maybe nobody is looking at this now but my dad was Dave Grassing. In the late 60's he and my mum set up a company called Dami Marine ( it stood for Dave and Midge) to build Lockmaster Steel Hulls, constructed in New Mills. I think they may have made about 25 with some having tops put on in Middlewich, for those that requested one. One or 2 were sailed to Holland . My dad had a full time job but the object of forming the company was to afford their own narrowboat. One or 2 are still around but no idea what happened to my parents boat "Bee Bee" after it was sold around 1978. T My dad passed away in 2016 and my mother earlier this year but I have not as yet sorted though anything related to their boat building era.