Due to our hosting and SaaS business, this involved a huge amount of time and money (legal fees for GDPR compliant contacts in particular) and we eventually fulfilled our requirements with our SaleFaith GDPR FileMaker WebDirect database.
In case anyone is interested, I’ve lifted the following from my original community post as we worked towards GDPR - FileMaker Community (English) where a (slightly out of date, light on data and read only) demo version is still online at:
https://demo.dbwan.net/fmi/webd/SaleFaith%20GDPR
User name: GDPR
Password: May25th
Good luck with everyone who is involved with this at the moment.