I'm a makita man, bhp451. The good thing about the makita 18v is the vast range of other tools on the same battery platform. The bad points were the early makita batteries had a few problems if not recharged regularly but has improved (and so hass their customer response to this).
If you're going to spend more check out milwaukee. Did have a look at the new bosch cool battery range and if you look into their brushless tech marketing it is impressive, makita do brushless too but I have not tried either of these as a user so can't validate their hype,.
If you want to spend less then look at the Ryobi One range.
do not buy the 453 that is on offer at wickes
it is vastly underpowerd
it has half the torque off the bhp451