>> .. but my client wanted it on an EIP browse 
that'll come, but probably not for a build or two.
>> I think I will find this useful on a couple of other forms I am using, but by the looks of it, it will only update the current field contents. 
you're not looking hard enough <g>
>>  It would be good if, like the lookup validation, it could populate another field as well, 
If the field is also a lookup field, then the lookup settings "More Assignments" will happen after an auto-complete as well. 
I will tweak it I think to allow this "More Assignments" on the auto-complete (without lookups) as well.
cheers
Bruce