I responded on your previous thread OP, because DS2 is Sullivan (he's 6). He prefers Sully or Van because he says Sullivan is too long to write. I call him whatever springs to mind!
Our surname is also a Scottish surname (Ramsay) and it flows well. DS1 also has a surname as first name.
We don't live in the UK so there is very little "classism" that exists around naming conventions here (Caribbean). Massive mix of Brits, Aussies, American, Canadian, Jamaican and Caymanian.
We got nothing but positive feedback when we named him, and honestly if you love it go for it. You can have an opinion on a name that has been formed from a different influence, but when you meet a baby you love with that name, it changes your opinion.
For example, I think the name Ptolemy is a massive wanker name, genuinely because it sounds so try hard and the only person I met with that name clouded my judgment. But if my sister were to have a baby name Ptolemy, my opinion would change to one of love, because I'd see my baby nephew named Ptolemy, not the dickhead I used to know.
Gathering the opinion of strangers on Mumsnet is a bit futile because all posters will offer their preconceived opinion of a name.
It's what you love that matters. If it makes your heart sing when you say it, then that's your name...
My Sullivan was either going to be Sullivan or Lachlan but he was born on St Patrick's day so it had to be Sullivan. In my heart, from the first time i heard the name I knew that was for him.
Named after one very hot actor as well (Sullivan Stapleton) and I'm not even ashamed to admit it 😁