Custom fastners in Newtown Powys do list a set mail order, I've always found them good to deal with and found them competative. I've never had to order stuff though as they are only 20 miles away and I work in that town anyway. Worth asking them if the set includes rocker cover bolts as I think it might not, you'll probably find button head allen screws are needed as extras as normal allen head screws foul the tappett covers - I'm geussing on this as it was a problem on my very similar 550/4's and I did them a long time ago so cannot recall if there were definately rocker cover bolts included in the set or if I needed to buy some for a different engine.
