I know this is quite a common question but i dont ask forums without doing a little bit of research.
I am using cloudflare and have a subdomain netherstowe.synthsmart.com and a main domain synthsmart.com
I don’t agree with you there. The domain already points to that IP, so the subdomain that points to the domain takes the records the domain you point it to has, which will also work fine for all of us. And in fact, the domain and subdomain the OP posted both work fine for me as well, so this change is superfluous.
@synthsmart-bedsdrout, if your subdomain didn’t work before, try now because it took a while for the record to propagate and if it still doesn’t work, wait a while and clear your DNS cache.