I expect this is really obvious, my apologies I couldn't find the answer on my own...
I've added a new field to customerUser by defining the field in the database, copying the CustomerUser definiton from Defaults/Config.pm and adding it to the main Config.pm with the new field defined (I believe this to be the correct approach as dynamic fields are not available for the customer?). The new field is showing up within OTRS

I'd hoped that the input field on the adding / editing customer screen would then use the size of the database field (i.e be a multiline text box in this case) this doesn't seem to be the case. What's the best way to modify the input box size so that it reflects either the database field size or the size of the stored data? It's great that the field is automatically generated, so I do feel I'm missing the obvious
Many thanks