Hi boobook,What sort of songs are you looking for? Being a work-based choir, does that mean you are interested in workers' songs or does it just mean that you are a choir which gets together in your workplace?
If it isn't specifically work-related then I have 3 song books which we used in school (yonks ago) called Sing Care Away. The arrangements are very nice (in my opinion, and I love part singing) and the songs are traditional British & Irish songs, mostly - although a very conservative collection. Not all of them are SATB but there are some.
I'm in Newcastle, Oz, and I'd be very surprised if you couldn't find at least one volume of this set in a good music shop.
I just did a search on Google.com and found at least one second hand book shop in Oz which has them.
Click here http://members.ozemail.com.au/~dacapo/catalog/30.htmHelen