I recall when a band of singers entered The Black (or was it The White) Swan in Kelso during the Both Sides of The Tweed fetsival circa 2000 and drove out the musicians. They seemed determined to make a point.

Anyway, let's not start the musicians v singers thing again.

When in Inverness, you could try visiting Ardersier Folk Club. It's a very friendly wee club with a good mix of songs and tunes although they have guest nights too.

There's plenty of traditional music in the Inverness pubs but it's just stuff laid on for the tourists and local pub crawlers.. Mostly very commercial and light weight although there are actually some good musicians involved. They just don't get the opportunity to do themselves justice.

"Macgregor's and Hootenanny's do sessions of sorts."

Again, good quality musicians but often "fast and furious" with many more participants than seats at times. Generally, better music than the pub entertainment though.
There's plenty of music in town but more relaxed and/or smaller sessions are harder to find these days.

They have a monthly session in Encore une Fois on a Friday(I'm not sure which one) which is very good and less hectic than the others. It's purpose is to raise money for the local food bank.