The information on the website is very vague as well: http://www.hsbc.co.uk/1/2/security-centre/secure-key?HBEU_dyn_lnk=SecurityCentre_Overview_BannerSlotA_LearnMore_Button
Here's the one I got from Taiwan HSBC:

And the one they plan on offering in the UK:
By and large im pretty indifferent to HSBC, they're no better or worse than most high street banks these days, but I can't say Ive been too impressed with HSBCs UK operations since being back in the UK, and their delay in providing this vital security service to UK customers. Rant over, but if you too have some vented frustrations against this here seems a suitable outlet: http://fuckyouhsbc.com/