From a pilot's perspective, can only say that your orbit seemed exactly the right thing to do. If the ATCO wants you to do something, it's his responsibility in this situation to make it clear.
Your orbit reduced risk out of the situation....
Clearly the ATCO was right on the limit of how much traffic he could cope with, for which one must have sympathy, and you were helping him out I would suggest. The only bad that came out of it was a resequenced finals.
IF you had an aircraft behind you steaming in to your position, you probably would have heard him on freq doing so and he, in turn, may have had to make a similar decision to you knowing you were there, short of any further information from the ATCO.
ATC informing you of your sequence number seems at times like a nice extra piece of information, but at times like this it's crucial decision-making data and should help re-inforce in ATCO's mind what his plan is by stating it.
I know there's some controversy on this, but it's a shame that entry point/circuit orbits are not routinely taught in the PPL unless you fly from a busy airport. The thing is you'll end up having to do one at some point and it should be unthinkingly part of your toolbox of options rather than just ploughing on into an unknown/unclear situation (you mentioned you only had about 15-20% of traffic visual, right?!?)
Any thoughts from ATCO's on my take?