Thanks again for the help. Being a novice, I couldn't really work out what to put where in the style.css file.
If you do ever feel up for it, or anyone else reading the thread, can you possibly give it a go?
This is the link for Sigil
This is for Adobe digital editions which you can check the produced epub with
I've also attached a couple of the most common fonts used in normal Arabic books and doc's.
And finally, theres an Arabic epub to try out.
Thanks in any case