Bought mine a few years ago from BCABLES on ebay, they still sell the kit here but the price and postage has gone up a lot since my purchase
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You will also need a 20pin to 16pin changer cable to plug it into the under bonnet diagnostic socket as the 16 pin OBD socket inside the car under the steering wheel only reads the engine and gearbox modules. The round 20pin will read all modules on the car.
BMW Scanner 1.4 is also worth considering as that is less complicated to set up and run., also available on ebay but still requires the 20pin to 16pin changer cable which is available on ebay here
https://www.ebay.co.uk/itm/303916282668?hash=item46c2d2732c:g:~KcAAOSw~FFgScSy
INPA is a big file and takes up a lot of space on a laptop, I have an old Windows 7 laptop that I keep with all the diagnostics I have which includes INPA and its associated programmes, BMW Scanner 1.4 and Gendan Engine Check Pro. Have a Creator 310+ which is standalone and portable which is quick and easy to use. That paid for itself when I had an airbag code none of the other systems could clear the Creator cleared it first go.