"The SHTxx are I2c"

2-Wire serial, yes - but not I2C (TM).
(See this thread)

"so code's no problem to a man of your calibre"

Ahem... well, err, of course not! ;-)

However, Steve did specifically cite it as a beginner's project.

"You can get samples from their new UK distributor 'Hero'."

I got mine direct from Sensirion:
http://www.sensirion.com/sampling

See this thread.