Thanks eschwartz, but its fine. After fiddling a little I'm happily using your example with a small edit:
{title}{series:| (| }{series_index:||)}
I like the fact that HarryT's example sorts the series order correctly, but I prefer the book title listed first. Thanks again to you both, now I don't need to even bother with collections; I can either randomly choose books via the cover view, or sort by author to browse and at the same time easily see which books are in a series.
So I don't even need to bother with the boring bit of figuring out what it actually means.
I'll just continue to avoid the firmware update to avoid any hassles with old collections or nags about books not being in the cloud etc and that'll keep me perfectly happy with how my PW is set up. In the meantime, hopefully Amazon will come to their senses and make some changes to the firmware.....