I have looked through the forums but was unable to find anyone with the same problem as me.I have water under the seat (but not the carpet)and am unable to find where it's getting in,the bottom of the door fabric trim is wet too.

Any ideas???

It will be coming through the door ancilliary carrier, between the carrier and where it is attached to the door. It ia very well documented on this site. This thread will provide the information:

http://www.briskoda.net/forums/fabia/damp-inside-rear-doors/79702/?highlight=fabia+door+leaks

rear washer connector, it's behind the trim panel next to your left shoulder