I used to use a program called 'Vagcom' when i owned a Vag group car a few years back, and by logging the torque and RPM you were able to get a fairly accurate BHP reading.
If i remember correctly, the formula was:
Peak torque X the RPM at peak torque / 5252 = BHP
I don't know if this app uses the same formula, or if the ECU already knows this figure and the app just reads it, but it seems to be fairly accurate IMO.

Thanks; I'm aware of VAG-COM but my reason for using Torque is that I don't have a Windows laptop!

As far as I'm aware VAG cars use 'data blocks' and it's one of those which VAG-COM monitors for torque.

Really I'm wondering if Torque calculates torque directly like VAG-COM does or does it calculate it from other parameters, e.g. MAF reading / 0.8, which would be less accurate, but which other diagnostics sometimes use, such as Liquid BHP.