I have some old foundry models which use spectreHDL for some elements but I find these are no longer supported in spectre.
Which was the last release which supported spectreHDL?
Also in some related models I came across a reference to a shdl2vloga spectreHDL->Verilog-A porting script. Was this something provided by Cadence and is it still available?
spectreHDL stopped being available from MMSIM61 onwards. It wasn't "supported" for some time before that, but it did run in spectre in MMSIM60 and IC5141. So those are releases that came out in 2004.
I just sent you (by email) some scripts to do a conversion. These aren't by any means going to be foolproof or complete, but will probably handle most code. I didn't want to post them here because they're just a bit of AE ware that has not been touched in many years and I don't want to give any impression of support or completeness of these scripts.