So the SC2500's that were dropped on Britain were probably carried by
Do217's?

Both the Do-217 and He-177 carried the SC 2500. The He-111 was limited
to the SC 2000 (which is seen in the background of many photos of that
bomb).
The almost completed He-274 and planned Fw Ta 400 could have carried
the SC 2500 as well.

Rob

p.s. Please note that the SC 2500 MAX was rarely used.