Although you are within the JAA Class 1 Medical limits, you are NOT within the UK Class 1 Medical limits for an initial application. I know, it doesn't make sense, but as an ATCO you need the UK Class 1 Medical (not the JAA Class 1) and as such it is not a NATS requirement, but a CAA one.
The UK Class 1 Medical eyesight limit for an intial application is -3 (it is -5 for a JAA Class 1). Whereas the renewal limit is -5 for a UK Class 1, it is -8 for a JAA Class 1. The doctors will allow a little bit of leeway (hence the NATS policy of -3.5) if your eyesight is stable given your age. When I got my initial UK Class 1 my eyesight was -3.25 and I got it.
Apparently there are plans to bring the UK Class 1 in line with the JAA Class 1; they have been talking about this for a while now. I had this discussion with the CAA Medical branch a while back. See this post:
ATCO Medical
As far as I am aware, it hasn't changed yet. Give the medical branch in Gatwick a call - they'll be able to clarify.
Cheers
p.
