Thanks Dave that is most helpful, I believe that Avon's are standard fitment on the new Aeros.
They are and they are, IMHO, shockingly poor and do not instill confidence.
You've already mentioned the tyres many of us run on our Aeros in your original post - using the Search function in the Aero forum, using the tyres as your search term will yield some good reviews - and they all have pros and cons (most personal opinion).
I personally like Toyo Sport Proxes but some people find the sidewalk a little too soft; they are a good compromise between performance and ride comfort. If you are a GRRC member, I believe they have a good offer for members.
A quick search in the forum revealed this
topic on replacement tyres for the Morgan Aero 8 
