I've now thoroughly sorted out the photostream:
Firstly - here's the webpage so you can see exactly what i mean:
www eurythmics me uk/norma index html
I've set up a test link at the bottom of the page which is purely the entire photostream, these images appear in order as they should do, no problem.
The moment in introduce a tag the order goes wrong, so look at the first ten images, then click on the Annie Lennox Miscellaneous heading which is filtered using a TAG and selects the same 10 pictures, but this time the order is totally different.
Any assistance you can give would be much appreciated!