Definitely look like Phoenix rods to me.
If it is of interest I found the cheapest place to buy the Renault 4 shells, as used by Phoenix, is Rexbo in Germany (www.rexbo.eu). Particularly if you can share carriage with some other purchase/friend. This was before the Brexit sterling crash but as they are made outside the UK anyway, shouldn't make a difference. For example last lot of Glyco Renault Rodeo 6 (ACL_) 0.8 Part Number: 01-4133/4 0.25mm I bought cost € 19.19/set. Just saw currently STD & +0.25mm €22.49 (36% discount),+0.50mm €16,49 (53% discount)!!

Location: Beautiful North Hampshire

Wow! What do the Phoenix rods weigh?

Are the same billets machined for 1 1/2 inch?

Location: Auckland, NZ

Martin, you are right on price for Renault shells, but Jack has 1 5/16 crank so I think he can only get the shells from the normal suppliers such as Seven Workshop.
Vince

I'm a bit (a lot?) ignorant about Phoenix crankshafts and rods.

Are we talking about pressure fed big ends here?