On the 20% thing what if you had a bottom of the range £300-400 hard tail that broke and they offered you 20% off a new bike and you were thinking of a £3500 full susser? You’d be laughing then!
They have to set out a structure to account for all scenarios. They don’t have to but they sell of a lot of >£2k bikes to people who just want to a buy a bike that works and go out and ride it. Giving 20% discount helps retain those kinds of customers and is a pretty good policy imo.
The £200 swing arm offer is also a good one. Lucky they actually have some in stock.
The text above is odd though as they describe it as a ‘frameset’ which to me would be main triangle, shock and swing arm as that is normally a frame set. For definition I guess you would have to see what they sell as a ‘frame set’. But you should also check the book/warranty that came with your exact bike as not all will be the same.
PS headtube is obviously not part of the suspension. It is a static mounting point for the suspension. The headset is part of the steering system. The fork is the suspension. Bars, stem etc are attached parts and so on.