When I did my last sierra one, I drilled out the rivetts holding the metal bracket that the bottom of the dash screws onto under the ash tray area, made it a lot easier to just pull straight back then, just put in a couple of self tappers on reassembly.
I would shop around,(places the trade use) best rad stuff at mo is from Poland, but there's been a marked price rise here the last year or so, I'd expect to pay around £35.
The oe matrix were made by Harrison, but can never get a replacement one from them.
Worth seeking out a copper one, even if extra, as vastly superior heat output than aluminium.
tabetha