At 450 quid including batteries for a 125mm grinder that's a bit of an understatement.........I have been looking at the dewalt 54v flexvolt range. Pretty pricey though..........
I've had a bosch 18v cordless grinder for a couple of years, I use it a couple of times a week but nothing too intensive. It's got motor and battery safety cut-off, battery charge indicator and it's pretty capable. More than adequate for my purposes.