I've enabled VT in the Thinkpad's BIOS but VMware is still moaning: -
You have configured this virtual machine to use a 64-bit operating system. However, 64-bit operation is not possible. This host is VT-capable, but VT is disabled.
This is usually because VT has been disabled in the BIOS/firmware settings or the host has not been power-cycled since changing this setting.
Now I've definitely rebooted since changing the BIOS - the Thinkpad won't allow you to do otherwise.
This KB article covers the "problem" in more depth, and the VMware site includes a sweet little tool that you can boot up, via an ISO image, to determine whether this emulation is possible or not.
Will download from here later and have a play ...