hi new to this but have an octavia 03 so is that a mk1? having trouble with drivers rear door -folowed the guide on here and the lock gets power but not long enough to work the motor! so i presume cotroller (window motor) playing up mine has water damage to part no sticker but can make out a4 on end-all the ones on fleabay say a5-will it work as they are listed for mk2 please advise yours nigel

Mk2 won’t fit on a Mk1. Search for the member Devonutopia, as he’s always got Mk1 Octavia’s in for breaking and might have what you need. You’ll probably need the door loom too as when the pins corrode they normally take out the multi plug connector too. 

looks identical-but are the internals differant?

The O/S/R window motor should be part number 1U0959812B, and whilst older mk2's share the part number, later ones have a revision which is very similar in part number but not the same - it has an 05s added. Best to be aware of what you are getting in case you can't return it if it is wrong. For info - http://www.oemepc.com/skoda/part_single/catalog/sk/markt/CZ/modell/OCT/year/2003/drive_standart/252/hg_ug/959/subcategory/959010/part_id/2541584/lang/e