Leaky MGB GT

[Chris Davies <chris@thames-language.demon.co.uk>]

        Hi,

                I have a problem with water leaking in my MGB, which
appears to be coming from the offside inner (inner) sill. I've had a
good look and tried to find it, but all I get is a mucky hand and
eyestrain! This did happen a couple of months ago but it was coming from
the air vents and was easily cured by unblocking the rubber drainage
pipe from underneath the car. Has this happened to anyone else? I'm
getting really desperate!       
Cheers, 
        Chris Davies