Hi Martin,
Welcome to the forum.
The two locations you've mentioned are probably the best ones for spotting at the city. Another spot to consider is the mound between the Ikea carpark and the perimeter fence, at the layby where the buses turn around.
You can also spot from Victoria Park but you'll be restricted to head/tail shots. Could be useful if you're looking for head-on take-off shots provided 22 is in use
You can also spot from the north side of the airport however that is weather dependent (sun) and you are shooting from within an industrial area. Also a stepladder would be needed to clear the fence.
Hope that helps.