Which way bath rubber seal?

[ben100]

I’ve got a McAlpine bath waste & it’s come with the two rubber seals one for the plug (which is the bigger one out of the two in pics) & the overflow. Which way around do I put them as the plug one has one side with loads of lines compared to the other side which has a slight dip with one line. The overflow one has loads of lines & other side is plain.

 

[Madrab]

I've always put the against the bath surface, same as a shower waste.

 

[ben100]

I've always put the against the bath surface, same as a shower waste.

Sorry which side?

 

[Madrab]

oops, sorry, the ribbed side to the bath/shower