Look at it the other way round… what about the moral dilemma your mate faces?
Does he recommend to you that you pay more for a bike, just so that he can pocket some profit, or does he tell you to go and buy online even if he ends up losing a sale.
If he is really a mate, and it really is such a good (like for like) deal, then he ought to be giving you the correct advice.
However, if you don’t even talk to him about it, then he has every right to be hacked off.
This being a mate thing is a two way deal aye?