Identifying S3 Brake discs

[SJO]

Hi guys. 

Has anyone got any suggestions on identifying the S3 front brake discs on my 2009 (59) Mk2 facelift please? 

 

They were fitted when I bought the car some years ago. 

I've replaced the pads several times but not the discs. Could I potentially identify them via the pad numbers or is it a case of physically measuring them and counting the bolts etc to find the year of S3 they came off? 

 

Thanks in advance 👍🏻

[SJO]

https://www.mtecbrakes.com/brake-discs/audi/s3-1999/s3-quattro08-99-11-03

 

Cheaper than expected? 

99-03..Wonder if there were other variations in size 🤔