Issue with form - for some reason that I can not see

I have a form, of which I have done lots with no issues at all.
but for some reason 1 field will not post, even though it is showing in web inspector as posted.

If anyone can spot something I have missed as this is driving me crazy.
https://references.svpsl.org/references.php?id=1582017557&ref=2&tel=0411820261

the “user_ref” posts the number 2, but for some reason this just will not add to the Database…