Whitelisting Google Ads (& other services) in firewall rules

I’ve been using firewall rules for some time now to restrict traffic to sites. One rule I use for UK based sites is to challenge non-UK traffic. I have an ‘allow’ rule to whitelist IP addresses for necessary services. However I can’t seem to find IP address ranges for Google Ads and other services.

I’m thinking I could whitelist Google Ads etc. with a referrer rule, but ideally I don’t just want to trial-and-error this on live sites, it would be great to just know what’s going to work before implementing it.

Any help would be greatly appreciated!

Are you saying that you want people who click on ads for your site aren’t blocked from visiting your site?

No, it’s that I think Google Ads itself needs to be whitelisted so its API connection doesn’t get blocked by the locale rule.