Try using this website/parts listing:-
http://www.oemepc.com
That warning triangle is what I bought via ebay for £12.99 delivered, you might find it cheaper, lots of them being sold by scrappys.
The hook to remove the wheel bolt head covers is "extractor" 6X0 012 243, going by what ebayers might ask for that, it would probably be cheaper to order it in via a VW group dealership's parts dept.
Edit:- one item that really should get carried in all cars, but is not mentioned too often in these forum is, a high vis jacket sort of thing, there is a space for that in the UK spec'd cars, I think that it is a space behind the cover on the passenger side kick panel - it does seem strange that UK does not require us to carry them with us in the car at all times, my daughter's late 2009 SEAT Ibiza, has it space to store that on the driver's side in an exposed slot - so you can't forget where is it (meant) to be kept. The generic "kit" available from VW has 2 of these Hi Vis jackets in it along with a first aid kit, warning triangle (that does not fit the Polo storage slot) and some other things! Luckily, I chose an SEL spec for my wife, so it has the double depth boot floor - so the space below the top boot floor is full of "useful" bits and pieces and a first aid kit is stuffed along with another Hi Vis jacket at the left hand side of the boot - but that car does not have any restraining/securing straps fitted at that point.
Another Edit:- Hillhold, yes a handy function but you need to be aware when it will be "applied" and when it will not - depends on the angle the car is at and the selected gear, if in neutral I don't think that it will get applied. My February 2011 Audi S4 has the "full" version of Hillhold or whatever Audi call it, it seems to stay on "for ever" and only get released when you ease up the clutch pedal - I'd think that there is a time limit but I have not reached it yet! Also, as it has an electric (I hate them!) handbrake, if you is in Hillhold mode and open the driver's door, the handbrake gets applied and Hillhold is disabled which is smart/handy/okay! One thing is that you can switch the Hillhold function off in my S4, if you want to, actually the switch is there only to let you switch it on if you want to use it, I never used it until my wife got her new Polo with that function in it!!
Yet Another Edit:- yes you are correct in that the Hillhold function is part of the ABS block and it just closes the valves for a short period in time, so the brakes will only hold as "well" as you have pressed the pedal.
