Am wondering if I could use elements for windows on my laptop,whilst on site, then when back at my desk use CS6 on a MAC on the same images? I have a windows laptop am not using at the moment and it makes sense to use it rather that purchase a new apple machine
Yes. PSDs are cross-platform compatible. Photoshop CS6 supports all the features of Elements. Going the other direction, you will be able to open files from Photoshop CS6 in Elements, but may not have access to edit using layer types (3D, Smart Filters, etc) that were created in CS6.