Back dated ESA

Hi,

Recently I migrated across to Universal Credit.

I've also been placed in the Limited capability for work and work related activity group and will receive the LCWRA element in my Universal Credit payment.

I understand that I will begin to receive the LCWRA element in Universal Credit after 3 monthly assessment periods from the date I first submitted medical evidence (such as fit notes) showing that my condition limits me to how much work I can do.

Am I correct in thinking that the LCWRA element of Universal Credit is paid from the 14th week onwards and after an assessment period of 13 weeks has ended?

Had I applied for ESA would these payments have been backdated right back to the time I first submitted medical evidence/ fit notes (In other words would I have been entitled to receive payments for the first 13 week assessment period under ESA which differs from Universal Credit rules whereby I don't receive the LCWRA element until after a 13 week assessment period)?

I'm finding online information on the subject difficult to understand.

Any information would be greatly appreciated.

Regards