Used a Makita, had my Milwaukee now for about a year use it day in day out and would never go back would highly recommend the one below, worth the extra money by miles for me personally MILWAUKEE M18 CBLPD-402C 18V 4.0AH LI-ION REDLITHIUM BRUSHLESS CORDLESS COMBI DRILL
Makita is a decent brand and it makes sense to use your existing batteries so I'd look for a bare unit impact driver or combi drill (if your other ones broken) then consider buying a bare unit circular saw or a cheap corded chop saw. You'd be well equipped to tackle the decking and pallet furniture and probably still have a few quid spare from £200.
We do need to dig out some old concrete posts and erect a new fence. Reckon I could persuade Will we need one?