Just done another BT speed check some days after fitting i plate. Whilst overall [first BT speed check/test] was short on the values derived from internet sourced speed checkers, the second BT speed/test showed a green bar value of 99.5% of obtainable value, which is a gain from the previous BT test values obtained before.fitting the i plate.
So my conclusion is that on my shortish connection [<500m including a bloody overhead!] whilst the speed is a nominal 6.5M with the i plate fitted I'm getting more correct data to the router thus useable values have increased. Slightly.
No forecast of Infinity, probably due to the same overhead.
cheers all and happy surfing,
gr.