Diversity of two single ovens?

[ban-all-sheds]

Compare the following:
Standalone all-electric cooker (four hobs, single oven and grill)
Electric hob with separate single oven (which includes a grill)
Electric hob with separate double oven (including grills)

I contend that all the above (in a domestic environment) would be viewed identically; diversity would be calculated on the sum of the loads. Thus, wherein lies the problem with the OP's setup?

More than once here I have posited taking an angle grinder to an electric range cooker to divvy it up into 1 hob and 2 ovens and asked for an engineering-based explanation of why if you did that the "3 appliances" would suddenly take more current than the cooker did, but so far I have not had one.