Wish you luck but it'd be the first I've heard of anyone receiving 'goodwill' after they had a service carried outside the dealer network. I suspect the answer will something along the lines of - "If there was a manufacturing fault then our approved service agent would have noted this at the 1st service ( 15k ? ). Defo no harm in trying tho, I'd be doing the same.
Regarding your earlier post, Skoda UK or any importer for that matter, do not 'hide' behind their dealer network as their job is only to advice and liase - basically try and keep the customer happy. They have to rely on their dealer network physically examining so have no option but to refer you back to the dealer. They should have a complaints procedure to follow if you wish to complain about one of their dealers tho. From our point of view, Skoda UK is just a person behind a desk who, to be fair to them, will also work for VW UK, Audi UK, SEAT UK etc.
It's a bit off your dealer provided poor customer service and then charge prices higher than advertised. It's up to the individual dealer if they want to reduce prices to compete with local businesses, but I've never heard of one charging more than the advertised price. What were you having done and what price did they quote you?
As for rougue dealers, every manufacturer is the same. You mention Volvo. One of the most frustrating experience's I had was from a Volvo dealer in Glasgow who seemed to see problems at every corner, the Perth dealership sorted out the issue without blinking an eye. Guess which dealer received all my future business when I owned Volvos. Vote with your feet is my advice.