I was an Operator Maintainer Sensors Submarines (hence OMSSMretd) so operated the equipment and carried out very minor maintainance. The basic design of the bow array is the same for 2020 and 2074, I believe it is based on 2001. But you are right in saying that any differences are under the casing.

Trust me mate I served as a sonar operator on both Triumph and Trafalgar and have opearted both 2072 and 2007. Ive had a better look at the phot and it dosent look like a complete installation. Both Trafalgar and Triumph had tiles over the flank array with Trafalgar this was post refit (2nd commision)
it looked nothing like the picture above. I would say that this is some sort of temporary housing. Tom Clancy is good writer, I was there on the day he visited Triumph he was there about 4 hours. I had 6 years experience working with this equipment.