Hilti are worth taking a look at. You will get them at a deal price & probably a few things thrown in. Trouble is, as with any top of the range tools, they just have "steal me " wrote all over them!
Millwaukee also do seem very nice. You could also take a look at Metabo, which are decent.
Your £450 will get you top of the ranges combi & impact kit.
Millwaukee Fuel kit (it is brushless - lighter, more powerful, uses less power, long life motor) is about £450 inc vat.
Hilti kit is actually 22 volt & is probably about the same cost if you go to a Hilti shop or rep.
I've got the dewalt DCK250D2 brushless combi drill and brushless impact driver 2x2amp batteries, had makita before which last ages and got a lot of abuse but I find the dewalt a lot better especially on hammer.
I've got to get a couple of 4amps as I've got other tools in the range and they eat up the 2amps to quickly. You can get that kit with 4amp batteries aswell
The new makita combi drill throws out a massive 105nm of torque wich is biggest in range the new compact impact driver also is highest rpm in its class and all new makita gear has overload protection similar to milwaukee redlink all be it not quite as good. New milwaukee fuel combi drill hasn't got good reviews with many former usesrs wishing they kept the old combi drill.
hang on a minute I'll go find the makita kit and link it
Right here's a kit with the drill and the older brushless impact. The new compact impact driver has been out a fortnight so probably not going to be in a kit for a few weeks but I'll link the compact one separately Makita DLX2040TJ | Makita 18v Li-ion Brushless 2 Piece Kit - 5.0Ah
Thats what I was referring to earlier - all the top of the ranges of the professional tools are very expensive. Expect to pay near £400 upwards for a combi & impact kit with 2 batteries. I am not pushing Hilti, but their prices are much cheaper than the above Makitas.
Dont worry too much about the amp hours rating of batteries as this only means how much time the battery runs - it's 'fuel tank' capacity if you like. A 3 or 4 amp/hr will last long between charges & all are same power output
Metabo are VERY GOOD tools but thermal protection can inhibit them.
that Bosch drill recently got voted the best 4 pole drill ever seen.
the dewalt kit is becoming ever more popular plenty of guys here use it and love it.
in fairness your not going to go wrong with any of them and unless your an oath you'll never truly exceed their limits in day to day use.
your far better off picking a platform you are comfortable with tools these days get you hooked on one battery platform once you buy one tool seeing you have the battery you'll buy their body only gear bassed on that. Get to a shop and hold them feel what's comfortable just don't rely on b and q etc they aren't the quality you'll find in proper tool shops