I have put out several feelers asking about a memorial for Calvert. One source has returned the information that Mike Calvert was very much the 'black sheep' of the family and this may have a bearing on the situation.
After exploring some very well informed Chindit sources, there is no knowledge of a memorial in existence for Mike Calvert. Helpful suggestions have been the RE Museum at Chatham and the SAS at Hereford, both of which have been discussed as possibilities before.
Regardless of the latter misfortunes of his life, there should be somewhere recording his memory, his achievements, and his passing...