Agree. As a minister in government you are effectively held to a higher standard than the rest of the electorate - ministerial code being the prime instance here. And while I have no issues with tax efficiency, those who berate anyone who is doing legally allowed tax planning and calling for higher taxes on people should not be surprised when their own tax efficient dealings come back to bite them.
One small detail is that this didn't happen. Rayner was not trying to be "tax efficient" or to avoid tax. She was trying to deal with her Son's trust and purchase a property. Like most of us would do, she went with what the conveyancers said and didn't really look at the boiler plate about seeking professional tax advice yada yada yada.
If Starmer had any cohones he would be pointing out the abuse of tax laws by Farage, Ashcroft, Rees-Smugg, Sunak et al. Patriots all.
Rayners crime seems to have been not being rich enough to avoid tax properly.