We bought a TPLink Powerline adapter kit here recently. 2 plugs in it. 1 plugs into the back of the router and it sends the WiFi signal across the powerline. Second one plugs in and takes the signal in the powerline and transmits a WiFi signal from it. Also has an Ethernet port to plug into if you want. It’d be ideal for your application, provided the house and workshop are coming off the same power source.
https://www.currys.ie/ieen/computin...adapter-kit-av600-twin-pack-10153178-pdt.html
This is the kit we got. Be wary of cheaper ones as they sell something very similar but it’s just a range extender, not a powerline kit. You can also get the powerline kit without the WiFi part which makes them cheaper too.