Thanks for all the help. Yes, "squiggle" is a very vague term,but I can't think of another one for this design! Brownowl - I'll try those 2 shops after Christmas - thankyou. I know I've seen this fabric before, so I'm hoping it's a fairly standard one that I'll be able to locate, but it's difficult to see this sort of design clearly online and hard to narrow a search down. I've tried quiltshops.com, but thanks for the other links.
Unfortunately I have sewn my blocks together, and am too near the end anyway to introduce another fabric. I could change the size from 5 blocks square to 5 by 4 or 4 by 4, but it would be a bit small, even with generous borders.
Part of the reason for running out is that this project has been so jinxed, and I've remade several blocks. Plus it's paper-pieced and I've obviously not taken enough account of the waste that results in. I'm actually going to run out of 2 of the 3 fabrics, but I think I've located the other one on ebay.
Will post a photo if I can get the detail of the pattern to show up.