Yes mate, I know it is. 93 RON in the US is made with the AKI and MON. Therefore IS 93 is UK 97.4 aka Super Unleaded.
Here's a conversion chart that uses the formula's:
http://www.pencilgeek.org/2009/05/octane-rating-conversions.html
Plus the ECU should in theory read and compensate for the different octanes by retarding the timing and lowering the maximum boost output, even if it is slightly worse. Sticker on fuel cap says use Super Unleaded only. Like I said, seems to be running like a champ at the moment. Obviously if available and near by I'll put the 99 octane in...
Thought I'd share it with everyone [emoji5] It's very easy for the unaware to look at the two numbers and think US fuel is **** compared to UK. Much like a US gallon and UK gallon.