The Mercury is a great bike , but maybe a bit similar to your Touring bike unless you do a very light build to make it nimble.
The roholf is not as sporty as an Audax with derailleur gears , but obviously great for minimum maintenance etc.
I have an old Touring Bike which stays in the shed much of the time , but does come out occasionally if left outside the gym on a dark winters night or a salty road day, I do thinks its a bit of a waste and like yours rides a bit dead unloaded but we have many happy memories ( esp when it was my only mode of transport and I did an annual mileage of over 10,000)
If you have the space keep the bike for bad weather and salty roads if you go out in the winter as its likely you are not quite attached to it now as you were and possibly even put winter tyres on it for the occasional bad days in winter , but you can just grab it and go without faffing with wheels and tyres.
Or set it up for night riding, ready for action.
Its also nice to have a bike you could leave out when shopping and not worry about it too much as its not a major head turner with the bike thieves!!
Its always great chatting bikes, as we all have different ideas, once a bike is gone its gone!!!
Miss my Mercury, but equally love its replacement!!!
PS the CTC classifieds is a good place to advertise if you do decide to put it up for sale, but think carefully ha ha!!