https://sellercentre.ebay.co.uk/business/news/april2019/shop-benefits?#comparative-pricing

Currently Linnworks does not implement the use of comparative pricing and according to support has no plans for it.
It would be a real boost for potential buyers to know how much they are saving against a products RRP and should be easy to implement as a lot of linnworks users already have the RRP as an extended property as it can already be used when listing to Amazon.

This would be fantastic. It would definitely make LW/eBay users richer!

This post was from 2 years ago - it's already been implemented.

Hi Adam

What value does Linnworks send, do you know?

You set an extended property for example RRP and then map that in your listing template.
Then if your selling price is less that the RRP then it will show the strike thru.