Look, I want to emphasize, I'm not a lawyer, and I don't want to second-guess your lawyer. And most of all I don't know anything about the specifics of your case - and one year since pre-arrival does seem excessive. But I also don't see how long your file has been going on.
And background is I've heard people in various contexts throw the idea of a Writ of Mandamus around as if it was a magic solution, so I'm a bit skeptical in general whereas at times it really does have its place.
But it's also possible your lawyer is experienced and has done this before successfully in some cases - because government does HAVE to respond to it (as I understand), and perhaps there is a possibility it will 'shake the tree' and get your file loose.
Off the top of my head my thoughts are:
-is your lawyer giving you a good, solid cost estimate? It's one thing if it's just writing a letter/filing but if he/she needs to go to court, well, that gets expensive. (But maybe the strategy is not to go to court)
-have your ordered gcms notes recently? Not only because it would help find out what is happening, but I would _assume_ that's good supporting info for the proposed mandamus.
-if you have got recent gcms notes - what do they tell you about where it's hung up?
-Have you also written your MP, written the minister, called, written whoever you can think of? Those things are "free" if you do them yourself. They also have some chance (even if small) of shaking things loose.
(Even with a filing of a writ of mandamus I'd want to keep the public pressure on - maybe interest a journalist - for the same reasons. It costs govt money to go to court as well so if it's really just a screw-up somewhere, maybe they'll deal with it. But if it's a real issue and not just a bureaucratic screw-up, govt has WAY more money than you.)
Again, not a lawyer, not an expert, but perhaps these thoughts help a bit)
