Using Three 3 3-2-1 SIM in Mi-Fi

Does anyone know if Three allow use of a 3-2-1 PAYG SIM in an (unlocked) Mi-Fi type device? I currenly have a £5/month 1GB T-Mobile data SIM-only contract, but rarely use more than 200MB in a month, so could save some money here. Can't find any specific T's & C's on the Three website but then finding anything on their site isn't that easy

From 3 Pay As You Go Price Plans

"Pay As You Go plans do not allow tethering. If you would like to tether, you will need to choose a Pay Monthly plan and / or an Add-On that does allow tethering."

Unfortunately that isn't the case, they look at the browser headers.
If they notice a browser which isn't for a phone, they'll block the internet access.

In reply to a post by pcoventry76:

okay so with all the main browsers having mobile versions, how is that still possible?

The headers are different But also they can tell from traffic and sites visited and volume of data.

It should work fine, I've used mobile sims in dongles before and there was no problem...

There is no PAYG data on Three. They have one-month bundles, but not a single PAYG offering for data suitable for use in a mifi.

I have a couple of 1-2-3 PAYG sims that can and do get blocked after varying amounts of time when used in a tablet, or in the 3G dongle in my car stereo (used to get traffic info etc, never calls or browsing).

So far, taking the sim out and putting it into a phone, then making a call, resets it. But how long for, I don't know.

I wish I could find ANY uk network that does allow PAYG data without buying a block of data that expires, or paying ten times a sensible price, or suffering from hopeless coverage (GiffGaff/O2)