Berol (http://www.berol.co.uk), a division of Sanford, is from what I can determine the present successor to Esterbrook.

They're still selling Recorder desk sets that look just like they ever did. Supposing that the refills are the same as for the old Esterbrook Recorders, they're still sold -- just check the refill links on my linked Google search.

Did all Esterbrook ballpoints take the same refills? If so, provided that these are the same as the old Estie Recorders, we have a source.

(Maybe someone out there with an Esterbrook ballpoint can try the Berol Recorder refills; I don't happen to have one)