Finding Bracket Rail Arms With old Connector

[ElBarto]

Hello,

I've just joined these forums and couldn't spot the best place to post this as it's a really basic question.

I've got a shelving rail that was put up around twenty years ago, nothing wrong with it but I cannot find bracket arms that still fit the type of connection socket it has. I've searched quite a bit but can only find the more modern ones that have one or two straight lines to connect, I've added photos of one of the brackets I already have & the socket to demonstrate what I mean.

Does anyone know what to buy this from (in the UK) or even what the name of this connection would be? Or what to search for to find it as, despite my best efforts, cannot find them.

Thanks for any help.