Hi Michael,
The cost of the parts is a fraction of this. I went for OEM quality when I did mine and and it was under £200 inc vat and carriage for new discs and pads all round. ~£500 for labour seems a bit steep, but I do my own spannering so I'm not best placed to comment on labour charges.
I'd say shop around, if you're not doing your own work. You could probably do with a reasonable independent garage to help you look after her to keep the costs down 😉
Good luck, Russ