Hi Klaus.
Thanks again for your help. I think I will try getting some Verbatim DVD-R discs and turning the burn speed down like you suggest. I'm just pleased that it doesn't seem like I am doing anything fundamentaly wrong.
The frustrating this is, I was stupid enough to take the advice of some young whippersnapper in the electrical department of my local Tesco with regards to which blank DVD's to buy. I asked him what the difference between -R and +R was and he said "Nothing really. But get +R just to be on the safe side." I told him what I wanted them for and he said that Tesco's own +R discs would do the job perfectly. It seems I was a bit naive in believing he knew what he was talking about.
And as for knowing what Windows PCs like, I gave up trying to figure that out a long time ago. Makes my blood boil sometimes having to use one for work. We bought three new ones in our office in June, key functions have either stopped working or begun to work intermittently already. As far as I can tell, they mainly want throwing in the bin.
Anyway, rant over. Hopefully with those tips I can manage to produce a dvd which will play on one of the blasted things.
Many thanks.
BigTC