Anyone know how much Skoda charge to make up a set up number plates?

Skoda dont make number plates it the individual dealers. They can charge what they want for them.

Go to your local motor stores and remember to take proof of I.D. and your V5c docs. 

Halfords will do them from about £15 for a plain one, if you want extras such as UK or Euro flag then that adds a limitless more.

£10-£15 each in my experience.

Ebay is the best bet

Usually you can get 2 delivered for a tenner

No docs required either