oh well, thnx for the advice. I'll keep that in mind for next time...i may just have to scale them up or dwon in size ( which will unfortunately reduce the quality :S) unless anyone else has any other ideas...
Use the ruler tool (it's under the same set as the eye dropper), measure one of the parts e.g. one of the fins that fold up to form shelf buddy's body.
Now measure your original template, and do a simple calculation to see how many times you have to multiply the submitted template to get back your original dimension. E.g original is 4 cm, submitted is 6 cm so that makes 4/6 = 66.67 % magnification.
Now select the entire template that someone submitted, go to edit >> transform >> scale
Input 66.67% on both X and Y dimensions and there you have it.
You may need to repaste the document onto an A4 sized page to reconstitute the template. Be sure to set the resolution on the new A4 size page to be the same as your document that you're gonna paste, or the dimensions will get screwed up again. You can check the resolution of your document by going to image >> image size.