Thanks for the responses. In summary:
The yellowish background was originally inserted to replace shadows, props, supporting arms etc, so it is a constant colour 219,217,202 and easy to select.
The customer wants it changed to 210,210,210 as it is too yellow.
I need to create a reusable action for this as there are 600 bags.
I need to change a colour exactly so things like curves are out I think.
I have just "upgraded" Photoshop so maybe it is a preference problem or similar.
I attach a better screen capture.
The RGB values confirm that the wall has changed to pink 215,201,201 as shown in the Info Panel. The pointer is not shown but is over the background.
The Preview is turned on so what is seen should be the output and it is showing pink, the source is showing the current and the Result is showing the desired, but the Preview is showing something else confirmed by the RGB values being shown in the Info panel.