1.2 TSI reliability?

When she cold starts she will rev above 1k rpm for a short period of time and then drop below - I am assuming just warming up but wanted to check this is normal?

Yes, this is normal electronic choke behaviour.

Also gearbox is quite loud (on the exterior only) - googled this and seemed normal?

What exactly do you mean by your gearbox being "quite loud"? Do you mean you are crunching gears when changing? Is the gearbox making a whining noise when running? Please elaborate.

Also, aircon when it comes on has a very distinctive smell, wondering if this is normal? (my last car's aircon didn't work so not 100% on if this is normal or not!)

Most likely bacteria in the system (a common problem if aircon is left unused for any period of time, like the winter or when sat on a dealer forecourt). You need an aircon decontamination (which you can have done as part of the aircon service and regas you should be due for by now (given you, like me, are on a 63 plate)