Thank you for your insights Katherine.
I do understand that market value is a shaky concept with regard to domains, but I have found the 3 ballpark ranges suggested here extremely useful.
Yes, it will all come down to what they are willing to pay but at least, now, I have managed to work out what I am willing to
accept, which is at least as important.
As long as your focus is on the Netherlands, .nl is fine. From my observation, .com is not popular in the Netherlands proper, .nl rules: 5M+ domains for 16M inhabitants.
So if they are looking to expand their business abroad, not having the .com can be a disadvantage. But if most of their business takes place in their home country, they can do without your domain.
From my years in The Netherlands, and now the UK, where many businesses use the .co.uk TLD, I'm aware that there is a tendency to misremember or to mistype national TLDs as .com. For most types of business, losing a few percentage points of website traffic is acceptable, but it becomes serious if the business deals in confidential matters (law, finance etc) and emails start going astray. In general, companies in both NL and UK go for the .com first, if available, and their national TLD second; despite national pride, .com is seen as bigger/more credible. I could imagine, though, that Iceland is different.
Of course, as you point out, it all comes down to the customers perceptions, they might not even be aware of such issues; again, they will ultimately have a value in mind and that overrides all else.
Just because your domain name predates the TM, doesn't mean you can use the domain in a way that would cause a TM violation. Plenty of examples in UDRP.
I didn't want to get into the minutia of it in that particular post but, yes, you are right, what I meant was that predating the mark rules out one of the 3 types of bad faith (that you registered the domain with prior knowledge of the mark) and a strict interpretation of the rules says that the complainant must prove bad faith on ALL three types.
Of course, the system is deeply corrupt and the rules are often bent to allow just two or even one type of bad faith IF the domain owner has not paid for a panel rather than single judge. So, what I mean is that predating the mark keeps you safe if you are also clear on the other two: that you haven't impersonated, passed off or in any way benefitted from confusion between their business and your domain, and you haven't shown bad faith by trying to sell it to them or, in a broader interpretation, offered it for sale anywhere.
A company could throw a case against you but they would be on very shaky ground if you are in the clear in all three categories, and they would not have a hope if you are also willing to pay for a panel.