Awning curtains

Hopefully someone can assist me with a problem I have - as a newbie to caravanning, I have just bought a second hand awning (Isabella) but it comes without curtains. I have spent hours trying to find anyone to supply, but am a bit stumped without a size. 

As I will not be putting up the awning until we actually go away, I do not want to spend the first 3 days tracking down curtains once I have had a chance to measure it.

So my question to all you worldly wise caravanners - Are all caravan awning curtains approximately the same size? My awning size is an Isabella 1025.

Any help or assistance would be very much appreciated.