I searched and put banjo-lin in quotes"", Got some results, seems that it was bowed, plucked and strum. There are a few links in cigarboxnation and one similar on ebay, http://www.ebay.ca/itm/RARE-VINTAGE-SOPHISTICATED-BOWED-PSALTERY-F-...
Interesting instrument, like to hear what it sounds like.
Search 'bowed psaltery' on YouTube, there are quite a few videos, even a tutorial!
Look for UKELIN -
That's the most common name for the little bowed door-to-door novelty instrument. If you do a quick search under sold listings on eBay, you'll see the go for very little because they were sold in huge numbers, and folks didn't really learn to play them.
Thank-you Steve, Ian, and Frank for replying! Great leads and information. My curiosity is up so when I have time after recording grades for the first trimester I'm gonna try to get it working to see what it sounds like.
My interest was enthused by this instrument and I've just taken delivery of a ukelin from eBay, it was going for peanuts and even with the postage from the US it was cheap. It is absolutely bonkers! I've looked at the how to play vids on Youtube so there is someone who can play it, but I'm going to need a bow and looking at the strings they could need replacing some time soon. I have a feeling that this will be one of those things that will be taken down from time to time but never mastered. Along with the banjo, banjolele, harp guitar and all the other 'it looked like a good idea at the time' instruments.