Went to open front window (electric) on 99 Octavia and and glass fell down, have taken off panels and raised and locked window in place. Has any member come across this before and if so what is the repair? Is it likely to be the motor or is part of the regulator bust?

It's likely to be the regulator itself. Either the plastic clips/slides break or the cable breaks. Usually the motor is OK.

In rare cases, the glass sticks and come out of the clamps. If this is the case you will see the clamps moving up and down.

Pretty common for the clips on the regulator to break on golfs so i'd imagine it's a similar design..

have a look here for a push in the (hopefully) right direction lol

http://vwgolfr32.co.uk/windowregulator/

Such a common problem that VW do a repair kit. £38 IIRC.