Hmm, well I found a friendly repair place when I was buying an air filter for my mower and he took a look at the thing today for me.
Turns out I wasn't careful enough when bolting the blade plate back on and hadn't got it centered propperly; hence the vibration!
Nice guy solved that problem and the RPM one in all of 5 minutes and didnt charge me a cent!
Props to them- if your an Adelaideian it was Lawnmowers Plus up at Salisbury.