Agree with the above about the batteries. There really is no need to be carrying the extra weight of a 4 or 5ah on your tools unless you are in the trade and rely on the tools for all day site work or long jobs. If you can get a deal where they come with the larger ones then cool, but honestly the stuff I have done over the last 5 years+ with my Dewalt Combi drill and impact driver (18v lithium XR brushless range) has never let me down just using 2 x 2ah ones. This hasn't just been putting up the odd shelf. I won't bore you with the detail but they've been seriously worked out and just keep going. They charge pretty quick anyway even if they do run out. None of this half a day to charge like the ancient nicad ones. It's under 1 hour usually.
When starting out with your purchase for a decent modern day drill, most will just buy a good bang per buck offer at the time. This is fine. It's what I did, and it happened to be Dewalt, but could just have easily been:
Makita - at the time, this was viewed upon as the main competitor to Dewalt. Huge range of tools. I think it's still that way.
Milwaukee - some really good tools but when I looked, tended to be more expensive.
Bosch - Used to have a green (more basic) and blue (marketed as a pro range) but not as big a range of cordless when I looked
Hitachi, Hilti, Metabo - don't know much about them
Ryobi - At the time I looked, was more an up and coming brand in the UK and just becoming more popular and pushed hard at B&Q. Large range. Cheap.
These days it's all about the cordless lithium cell stuff as it's light and still powerful and very free movement with no wires. I'm sure you know this already.
There's no reason why you can't just buy the cheapest drill/impact kit and just then get other tools as required, like cheaper wired stuff. But what tends to happen is this...
You buy a modern day drill/impact set....realize it's a life changer having good cordless tools....get carried away now that you already have brand X batteries and therefore justify the expenditure of buying "bare" tools (ones slightly cheaper body only without batteries) because you need an electric planer in your life. Or an angle grinder. Or an electric strimmer. Or a jig saw. Or a router. etc.
So maybe have a look at what other tools you might buy in the future and consider that when picking what you buy into.
As for the drill. Yes get a combi drill and an impact driver set. I won't go into detail why you should get an impact driver. There are a hundred reasons why you should have both.
When I looked years ago, there was kind of 12v cordless stuff (cheaper and light), 18v (kind of become the standard) and then more heavy duty 24v+ stuff. If you can afford the brushless stuff that's cool, as they tend to be massively efficient and last longer on batteries. Also the tool / motor itself should last for a very long time. Some ranges have nice to haves like battery level indicators when you press the back of the battery itself. I personally wouldn't spend extra for a variable speed impact driver. When you are using an impact driver, it's 99% of the time because you want the power of it. Having said that, I use mine A LOT out of pure laziness because it's so light and compact.
Also when you are umming and arring over £20 here, or even £50 there.... this is likely to be something that you use for possibly 5-10 years...
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