Hi Louise : )

What management is on this car? Saves me looking it up at work tomorrow!

Have you checked around for air leaks, anything after the throttle plate? It's possible to get strange things happening when something is off in the inlet manifold area.
Also worth looking at is any warm-up sensor .. for operation or bad connections. One of these failed can alter fuelling cos the car thinks it is cold, when it's not!

Some management systems remember (they learn) tps/fuelling settings. Some can be reset by disconnecting the battery for a while. Before you try this, make sure you got your radio codes and set the alarm off with key .. or manually!