It can take up to several months. Patience is the order of the day. You can keep checking your MCOL history as it will update with the date they send you the N180.
In the meantime, you can simply download your own
N180 DQ, complete it online and have it ready to send as a PDF attachment to an email when you see notification that one has been sent to you.
In case you don't receive it for any reason, if the MCOL history shows that the claimant has submitted theirs, you can then simply send yours to dq.cnbc@justuce,gov.uk and to the claimants silicitor and CC in yourself.