As you weren't sure whether or not there was a headstone, I sought out the Locality Office in Ullapool to track down a Burial Ground layout plan using your clue of Lair #61.
The very helpful assistant remembered your earlier query and I managed to get a photocopy of the layout plan which made finding the grave very easy.
I'm attaching only a few piccies to save the forum's bandwidth, but I've also taken others showing the rest of the burial ground and the grave's location within. If you want these, contact me with your email addy and I'll send them direct.
Curiously, on a much lighter note, there were a couple of coincidences today.
1. I notice that Catherine died on my birthday, 23rd October.
2. I took delivery of my present car on my birthday, 23rd October 1991.
3. The first person I saw upon entering the Locality Office was an ex-colleague (who was visiting and haven't seen for ages) and whom I drove, as a bride to her wedding, in my car a year later!
So all in all, a successful/curious day.