OK, there are two pics on Chris' page. The first one has a flapper on the left!
I have only done this a few times with mixed results and I've bee able to see in real time the changes in oxygen sensor output.
Typically, the problem is not with the MAF, nor the TPS, but injectors or oxygen sensors, or both.
Check fuel pressure first.
Yes, I am still alive, and still in the Rover parts business.
Text me for greatest likelihood of finding me.
Dominic Perodeau/Global British is a thieving bastard, do not send him money.