I bought first Ducati when Peterborough was open and 30mins down road - they closed so now its 90mins to Cambridge for me but would travel further if needed so voted no However, I discounted buying a brand of bike this year due to complete lack of dealers generally but not due to location/distance of them
For me it is an issue. If something goes wrong with most new bikes now, they need diagnostics. They also need servicing by a main dealer if they are under warranty. If any warranty issues arise - then again we need that main dealer. If the nearest is many miles away as is the case with Ducati dealerships in south yorks now, its not really very good. A van would be needed (which I do not have) to get my bike to said dealer (and back). The less main dealers there are, means the busier the remaining ones will be - that can mean weeks or months to get a fix. Not ideal either. Its more than enough to put me off spending big money.
Living in C.London it used to be important over a decade ago, but there are no decent main dealers (IMO) here now, my bikes are no longer kept in London, I have van specifically just to move my collection around, and use the dealer who I feel will service it the best regardless of saving a few pounds.
For me it's an absolute yes. I'm not worried about servicing so much but more about warranty issues. Also my bikes tend not to get used in inclement weather. So a booking at a dealer a good distance away becomes a pain if it's bad weather. I'm now badly affected by the loss of Pidcock Ducati. Any other Ducati dealer is a good distance away, if I had to leave the bike for any reason I'd need a loan bike for certain and they seem to be few and far between. Or if it gets collected it's difficult to go and collect it. I'm keen on another new Ducati, but it's forcing me to look at another make.