At this time the ClientNotes field is a part of the main Client database
Hopefully you don't plan on one database per table?
Because of that statement, I'm not understanding if the conflict is because the notes and the rest of the fields are coming from the same table or query, or some other reason. I suspect they are, and you are using a sort of modal form to edit notes. This might explain why you had no success with record locks. If you have no locks, you will get warnings from Access that are sure to confuse the users. If the notes are part of the same record source, then would you not want Access to prevent editing of the notes portion of the record? I would think so, one reason to follow*.
Possibly separate notes into their own table and put them in a subform of the main form, assuming you want to see the notes while looking at the main record? If you don't need to see the notes related to the main record, probably even better. You should be able to edit the notes while another user has the same record open if the notes are not part of the source that populates the other fields.
* However, the notes would not be refreshed for a concurrent user viewing the main record when those notes are changed by someone else unless something about the process could ensure their notes view is requeried before providing the means to edit them. Of course, if I'm editing the notes and you attempt to do so at the same time, you're back to square one.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.