Had an interview with a lovely company a couple of years back but at the time they couldn't offer me the right role. They did indirectly approach me (through an acquaintance, quite casually) some time later but I was already with a different company by then. They now have another role available and got wind I was job hunting, but I'm finally settling where I am now and don't want to interview for anything else at the minute. They are expecting to hear from me, would it be courteous to drop them a (friendly) email to let them know I'm no longer looking at this time, or unnecessary? Desperate etc? I never know what to do for the best with these things. I just feel bloody guilty!