>Go check the price plans - Three has a SIM only deal for £27 with unlimited data, which includes tethering (aka personal hotspot)
Looks like everyone missed last month's 'announcement' from Three:
Three UK Quietly Removes Tethering Caps from 4G Mobile Plans
However, what does need to be clarified is whether Three have also lifted their restriction on using a phone SIM in a mobile broadband only devices.