@mntmn if you've got money to burn; tenable.io

If you're on a budget; https://hackertarget.com/openvas-scan/

Self-hosted; Greenbone OpenVAS: https://openvas.org/

For free; Look at your IPs in shodan.io ;)

@neil I'm sure the lovely folks at https://www.thecuriouslounge.co.uk/ would either be able to help or know of other good places (and curious is right next to the train station!).

I've held workshops at RISC's premises before; https://www.risc.org.uk/room-hire which is still reasonably central.