"The highest acceleration in a particular gear would be at the power peak surely?"
Here is modified the plot in the post #287 of V8 Fireworks:
The green curve "Accelerating force on the vehicle" has identical shape with the original torque curve.
At 60Km/h vehicle speed (i.e. at 16.7m/sec), wherein the engine revs at 6,000rpm, the engine makes its peak power (282HP / 207kW).
The relation between the power provided, the speed of the vehicle and the force acting on the vehicle is: Power = Speed * Force.
This means that at 60Km/h the force that accelerates the vehicle is 207kW / 16.7m/sec = 12,500N. It is the point P4 in the above plot.
Supposing a total vehicle weight of 10,000N (1,000Kg, 2,200lb), this gives an acceleration of 1.25g (g=9.81m/sec^2).
At the point P1 of the maximum torque, the vehicle speed is 37,5km/h (10,4m/sec) and the force acting on the vehicle is 14,600N. This gives an acceleration of 1.46g, which is 17% higher than the acceleration at the maximum power.
Worth to note: at the point P1, wherein the acceleration maximizes, the power provided by the engine (point P2) is: 207HP (152kW), i.e. it is more than 25% less than the peak power.
It seems strange: with substantially less power, the acceleration is higher!
If you look at it from the energy viewpoint, it gets simpler:
in order to gain 1Km/h speed when the vehicle moves with 30Km/h, it is required only the 1/2 of the energy required in order to gain the same 1Km/h speed when the same vehicle moves with 60Km/h (because the kinetic energy increases with speed square).
(31^2 - 30^2) / (61^2 - 60^2) =~ 0.5
If something is still confusing, please let me know to further explain.