In case anyone is interested -
Easyjet flies between Bristol, London Gatwick & London Luton and Inverness.
Flybe flies between Belfast, Dublin & Manchester and Inverness
On May 17, KLM is starting a daily flight between Amsterdam (Schipol) and Inverness. (That might be a good option if coming over from the U.S.)
A transfer through Schiphol, is far more reliable and way easier from a stress free perspective than a transfer through Heathrow. Heathrow should be avoided at nearly all costs. IMO. I usually see the inside and outside of Schiphol on average well over 100x a year. It's the best of the high traffic airport to go through IMO.
That would mean Delta from the US for routes that are not serviced directly by KLM. It's an excellent option. Even better is to stop over in Amsterdam to either warm yourself up or cool down after a trip up to the tundra. Some great golf here too.
Though missing the connecting flight out of Heathrow doesn't have to be bad either, if you are organized in advance you could spend the first day waiting for your flight to Inverness at Sunningdale, Walton Heath, St. Georges Hill, Woking .... and the list goes on.