I've had some luck reserving B&Bs by going around the backdoor. Google Maps will display small dots for lodging without openings for your dates, so I click on the dot, google the place, then email them with a query. In Oban, I even drove the streets in Google Maps StreetView and found signs in yards for B&Bs, googled them, and sent an email. In the latter case, I was also able to figure out if they had private parking based on signs. The "parking" filter on most booking sites are pretty useless. I've gotten a few successes from proprietors that just haven't opened their bookings yet, but did for me, and a few that have always relied on word-of-mouth to avoid paying booking fees. Of course I've had a few "sorry, I booked all of 2022 for tours" and "try back after the new year" rejections. I was successful enough to book our entire three week trip for next June with places that I'm quite happy with, and unlikely to change, even though they are all fully cancellable. I'm feeling so comfortable with the state of my plans that I've moved on to 2023 adventures :-)