I've just checked their web site, maybe you could provide a link to that offer?
I think you are confused, The HF Grips are £28.99 including the 30% discount and postage of £4.75 to £7 needs to be added to that.
I cannot find them at £29 less 30% ! Ducati Techspec Gripster Tank Pads
Their price including 30% discount for the C3 pads (which these are) is £32 they charge £4.75 to £7 Making the total £36.75 to £39.00
For £30 you get the Tank Pads, Ducati Badges and the Braaap stickers!
Were you wanting to make an offer?