I need some advise. I'm looking into investing into a valve amp for under £500.
I was considering either a Blackstar HT-5 mini stack, or a vox night train, but was wondering if there are any other suitable amps for playing Classic Rock and some Blues.
yes, examples please.

and btw, spellcheck...ADVICE!!
Quote by Mad Marius
DBZ guitars, love'em. Especially their Les Piccolo model.
Mainly stuff like AC/DC, GnR, Sabbath, Motorhead and Led Zeppelin.

Also, sorry, im awful at spelling.
Zepplin used Superlead Plexis onstage, but mainly page used a Vox AC in studio and a Supro valve amp, yes some will also say he used a solidstate vox (i have no clue if this is true or not)
ACDC just cranked up a JTM45 instudio and a bunch of other Marshall models
Sabbath used Laney all the way
GnR used a silver jub.(it's like a JCM800 in a way)
I have no idea what Motorhead used (well lemmy just used a Superlead Bass and cranked it)

So your best bet might be a Marshall clone eg: a Ceriatone 18 watter?
The Blackstar HT5 gets a really good Marshall sound, the guys behind the company used to work for Marshall. For those bands, I think it'd be very suitable.