Daft Shower Enclosure Question

[tonyglover]

I have a shower emclosure installed in an en-suite that's been there since we bought the house 8 years ago. We recently fitted a Mira XS power shower to replace the old gravity fed one which had packed up. During the install the enclosure b-fold door broke. The plastic lugs top and bottom that hold it together snapped (well one had snapped weeks before, but the other came out in sympathy as we worked).

Being a DIY numpty can I simply remove the old enclosure, leaving the old tray intact (it's in very good nick) and replace with something similar like the B&Q Barcelona Pivot door and side frame. Everything seems to be 760mm, whereas our tray actually measures 740mm x 740mm. Is there a variance in these enclosures as I'd rather not have to replace the tray if it doesn't have a problem.