Formula to return column reference of data looked up from another worksheet

Hi,

I have two worksheets, one containing data and the other contains a data load plus column references that link the load and the data together. The reason for this is that the load is a standard format and the data will be different.

I used formuals to link the data to the load using index / match / indirect. Where it doesn't work is the way in which the column references are generated - I have tried to use a vlookup within the reference but this returned an error.

Can anyone help adjust the formula so once the load mapping is changed the column reference automatically updates? I have attached an example which I hope will be easier to follow. Alternatively is my approach correct or is there a better way?

Thanks in advance - your help is appreciated.
Bob