It seems that Orange feels better supporting HTC's own brand rather than adding it to its SPV range. The HTC TyTN II is the Orange SPV M3100's successor and comes packed with GPS and a screen you can tilt. It's available from Orange on selected monthly contracts for around £90.
The Orange HTC TyTN II doesn't come preloaded with any sat-nav software so you'll need to buy your own, although you can use the free-to-download (not including data charges) Google Maps app to track your location and give you directions.
For more in-depth information on the Orange HTC TyTN II, read our full review of the HTC TyTN II.