SSL on Custom Domain

I think I've half got SSL on my custom domain working... wondering if anyone can help me with where I'm going wrong?

If I type https://gallery.edinburghphotography.com (My smugmug is on a subdomain) it works but any of these combinations doesn't:

• https://www.gallery.edinburghphotography.com
• http://www.gallery.edinburghphotography.com
• www.gallery.edinburghphotography.com
• gallery.edinburghphotography.com

I'm not sure where I'm going wrong to be honest. My current setup is Google Domains as the registrar for edinburghphotography.com, using name servers from Cloudflare.
Cloudflare has CNAME www.gallery and www linking to domains.smugmug.com

As the first link I put above works I tried a few rules on Cloudflare to redirect to that one: (the *s and the $1s represent wildcards)

• gallery.edinburghphotography.com/* to redirect to https://gallery.edinburghphotography.com/$1
• http://www.gallery.edinburghphotography.com/* to redirect to https://gallery.edinburghphotography.com/$1
• https://www.gallery.edinburghphotography.com/* to redirect to https://gallery.edinburghphotography.com/$1
  I've also got the 'Always Use HTTPS' turned on at Cloudflare.

As far as I can tell that should work, but it doesn't. This leaves me to wonder whether it is a Smugmug rather than a Cloudflare issue (hence why I'm asking here!), anyone got any ideas? I know Smugmug uses Cloudflare too which is maybe why there's some difficulty...
Would be really grateful for any help, hope the above makes sense and isn't too confusing!

Oh and bizarrely, the https://www.gallery.edinburghphotography.com/ link seems to sometimes link to gallery.edinburghphotography.com and other times leads to a 403 Forbidden error page!

Tom