When are additional MX records applied

[#1]

Hi Guys

I have added a couple of MX records via the plusnet website, however using the mxlookup tool 24 hours later the changes have not been applied.

Please can you let me know how regularly the updates are applied, and how long it should take before the changes are visible?

[#2]

When you say  you have "added a couple of MX records via the plusnet website", just what do you mean?

Which DNS records are you trying to update? Do you have your own domain hosted somewhere?

Generally, DNS records can take up to 48 hours to propagate around the world, but usually take less.