I have a head office with address range 172.31.254.0/24, and an pool of remote IP addresses 172.31.248.0/24

In my PPP profiles, I have setup a LOCAL address of 172.31.254.5

Is this ok to do? Should the local address be on a different subnet? or is it OK for all remote users (who pptp into the head office) to share the same IP on the head office subnet?

Thanks

yes thats fine but ensure you have proxy-arp enabled if you do it this way

ether 2 in this example is your local interface