Who created Custard Creams?

Exact quotes from cited website follow:

"History:
This is pretty sketchy stuff but the best bit of information I found on the origins of the Custard Cream comes courtesy of NiceCupOfTeaAndSitDown (see here):"
"The baroque markings are in-fact Victorian fern fronds which were in vogue in the latter half of the 19th century. The Victorians were also very keen on puddings and the new eggless Birds Custard powder introduced in the mid 19th Century was being referenced in the Custard Cream.

We believe that the Custard Cream was probably more likely Huntley & Palmers (Reading) rather than Peek Frean (Bermondsey South London) as Peek Frean claim that their first cream sandwich biscuit was the Bourbon, which seems to date more recently than the Custard Cream. Another company who dates from the same period and with a long association with the Custard Cream is Crawfords, now part of United Biscuits. Its entirely possible that it was indeed Crawfords who produced the Custard Cream, they were based in Edinburgh but opened a new factory in Liverpool in 1897. This is about the time the Bourbon was introduced (1910) which indicates that the mechanisation required to produce a sandwich cream on an industrial scale was in existence."
https://reshistorica.historyboard.net/t1047-biscuits-past-present-and-crumbling