Thank you everyone )) It hasn't yet sunk in I don't think...plus now it means have to start all the other malarky of sorting stuff to send, shipping, banking, etc etc....haha
LadyB, I'm not sure how the 190 differs from the 189 visa, but if the visa requirements show that a medical will be required it might be an idea to get it done becos they will request one from you anyway if it is a requirement. The only time you might want to wait for CO request is if you have any conditions, because then you will need a specific type of medical test. I had TB a few years ago so I had to have other checks done as well.
If I recall correctly, I had the LogIn for the online visa thing as soon as I was invited to apply, so I reckon you should be able to fill in the medical questionnaire which determines what sort of a medical you require, it will then give you a HAP ID which will allow you to book your medical. I booked my medical before the CO requested it as the questionnaire outlined the type of medical I needed to have done. I can't remember where exactly I got the link for that from though pretty sure it was a straight forward link that just appeared on the account page along the lines of "determine whether you need a medical examination". My advice on booking the medical is to go for one that does e-medical if you have the option (so submits your results online for you rather than gives you the results in paperform - it's much quicker and one less thing for you to send off)
Also advice to anyone who hasn't yet been assigned a CO and is waiting for a "request of additional documents", start filling in the Form 80 incase they request this from you. It is a very long form and asks for quite a bit of history so if you get started now...it'll be easier for you. Luckily I started collating info for mine early but didn't think they would ask me for it and I would be lucky, but sods law they wanted it! Either way there's no harm in filling it in. Also you are free to upload it anyway even if they don't request it, so they have more info and less likely to ask for more!
Hope the above is of some use to someone