XLookup using a calculated Array

[BaconMcSandwich]

I have an xlooup function I want to use however the lookup and return array's will chage. It might be that I want the lookup array to be A:A and the return array B:B. OR I want the lookup to be C:C and the return D:D.

I can calculate the columns I want to use (Either the alphabetic or numeric values) but is there a way to get my Xlookup to use the values I've calculated?

 

[BaconMcSandwich]

Thankyou so much for that.
I've had a quick go and it seems to be working. Got to do a little but of checking but so far it looks pretty perfect. Still getting my head round how INDEX is doing the heavy lifting but I'll get there.
Cheers