Tim - as Surreysinger points out, by no means all the songs in Henry Burstow's list were taken down, so you're bound not to find some of them.

If The Sailor's Bride you mention is Our Bessie Was A Sailor's Bride as shown in his list, there are 98 entries in a cross-index of the Roud #13808 (51 song, rest in broadside), so it seems to have been quite common. You could check to see if there was a lot of variation in the collected versions; if not you might reasonably assume that his version was similar.

Mick