I pushed hte boat out and got a replacement , new, presser bar for a "71", which did fit the "15". Took a bit of work to get the taper pin to fit snugly, but once that was done things have been looking up. Nearly all play has been removed and I'm down to 6 stitches per inch, which is as good as it's going to get on a machine where the original spec is 7 stitches an inch. I'm happy with it now, although I'm working on converting my home built treadle table (for a domestic) to suit the 29k. I realise the gearing will be wrong, so I'm using a reduction arrangement with two pulleys. Diameter of the treadle table wheel is 14". I'm taking that to a 6" wheel, then from a 4 1/2" wheel to the machine. That I'm hoping by guesswork of the diameter of the original treadle wheel at 250mm should give roughly the same gearing.