So indecisive

[#1]

Max Adsl.
I cant stop looking at my router stats and sitting on the fence
Atten 40.5
Noise varies from 12.5 to 19 but most of the time is 16
So may be I'd be worse off than I am now with a lovely fixed 2Mbps on PAYG
Is it worth the hassle?

[#2]

Why not put your phone number and postcode into SamKnows (here), click BT ADSL on the Availability page and see what speed BT Wholesale think your line might support?
Having got that it's up to you to decide if the extra speed would be beneficial for you.

[#3]

Try feeding your current stats in to http://www2.farina1.com/ADSL/default.aspx - it's pretty accurate I think.

[#4]

Hi,
Given your noise margin, I'd expect you to see an increase in speed of approximately 1.5Mbps.
(Going on 800Kbps per 3dB noise margin)