I need a couple too. I'll take the rusty bolts I have to my local fastener supplier tomorrow, they should have something similar, they'll be pretty standard bolts.
I'll let you know tomorrow (unless someone has some genuine bolts they'll give you).
They're 5 x 40 socket cap bolts.
I picked up a handful today.
Old bolt at top of photo, new one below.
£2 posted for a pair. (or ask your local nut/bolt merchant for some)