Usually most of the time I refrain from downloading from drop boxes if the OP won't at least try to post db here. I did, and no big deal for me to change my regional settings for testing. It's a bit difficult to recall every nuance of each post that we've seen so far, so what follows may not be a valid point.
I noticed something being done that I would have thought not possible and couldn't see until looking at the db. The DLookup is trying to utilize fields from different tables (tables includes queries) in the criteria portion. It's a domain function, so can we reference fields from other domains in the criteria expression? I would think not but I've never tried, believing all fields in the criteria must belong to the domain being searched. Mainly I'm asking my more esteemed peers, because if I take out all the variables from this expression
Code:
DLookUp("VatRate01","q02VatRate","VatCode01='" & [VatCodePurchases02] & "' AND DocumentDate01
Between #" & Format([StartDate11],"yyyy-mm-dd") & "# And #" & Format([EndDate12],"yyyy-mm-dd") & "#")
so that I have
Code:
VatRate99: DLookUp("VatRate01","q02VatRate","VatCode01='NV' AND [DocumentDate01]
Between #2017-01-01# And #2018-12-31#")
Access tells me that it "can't find DocumentDate01. It doesn't matter if it's DocumentDate01 or [DocumentDate01].
The use of multi-value fields isn't a great idea, sorry to say.