I can remember having the same feeling after I got my diagnosis. Fortunately, my ENT stressed the positive aspects of this type of tumor: almost always benign and slow growing.
While I never got totally comfortable with the idea of brain surgery, the more research I did and the more doctors and former AN patients that I talked to the more optimistic I became.
I agree with Jim, your AN is not large.
While I can understand your concern over radiation due to your previous cancer, you should not discount it as a very viable option for you. Due to my age, 43, and tumor size, almost 3 cm, radiation was not the best option for me.
I hope someone in the UK will give you some feedback, but until then keep doing your research and keep an open mind on treatment.