I have now fixed the issue. The issue was that I configured pi-hole and set up the dns server from pi-hole, but my router (community fibre) - although configured to use the pi-hole device for dns, did not allow clients to use the pi-hole for dns - instead in the clients (running ipconfig/all), the address for dns showed the router address, not the pi-hole address for dns. Eventually fixed it by using pi-hole to provide dhcp and disabling the router from giving dhcp. Another issue on the router is that ipv6 seems to be causing an issue - now disabled ipv6 on the router. al running ok using dhcp and dns from pi-hole.