You will need to contact the owner's representative to arrange access.
In the case of this object this can be done by:
Writing to D.j.r. Robinson at Forsters Llp, 31 Hill Street, London
Reporting A Data Error:
Reporting An Access Error to the HMRC:
Cameo collection - no.41 Bust with short beard
Maker:  Maker Unknown
Description: 
Cameo collection - no.41 Bust with short beard, cuirass and pallium, Antoninus Pius, onyx, the cameo however appears to be modern.
ID:  16923
THIS ARTWORK IS LOCATED IN:
LincolnshireThis item is available for viewing by appointment through the contact shown