It's a big investment for how often you might use one, unless it works for a living, as is the case with my lad, so I'm sort of with J&S here. A good set of spanners, hex sockets sets & a nice breaker bar, supplemented with a good battery driver, in my case a Dewalt sees me through; that does the Landys too. It's remarkable how much work can be done with an 8,10,13,17 19mm combination spanners, a pozi, a flat bladed screwdriver, in good condition & the ubiquitous hammer.
On the few times I needed an extra bit of yagadagadaga I burrow my sons large Snap-on, (no smutty sniggering please).
And which 1950s Scammel had you in mind John?
In your case the makita is the way to go, in my opinion. As you already have the battery and charger.
If you were coming at this with no battery, then the Clarke would be the obvious choice, again imho.
As to whether it s a justifiable outlay or not is your choice.
Although you have got me looking at compatible impact drivers for my Dewalt battery drill, damn you!