There is nothing hidden at the headline coordinates. You will have to do the Adventure Lab to work out the bonus.
To play adventure, either click this link: https://adventurelab.page.link/zKJ7 or scan the QR code below:
The final is at N 50 AB.CDE W 004 FG.HJK
I recommend wearing sturdy footwear for this cache. The route was partially boggy when placing the cache and will likely get worse through the winter months. There are signs asking to keep dogs on leads in this area, so please respect this if taking your dog with you. Care will need to be taken on the slippery surfaces.
13/12/23: New question and answer at the Silver Ball pub, new paint job and sign have rendered original question mute. Thanks to madmanacrossthewater for their message.