I have the REGA ISIS valve spinner and REGA OSIRIS integrated amp..... both came with the REGA Reference mains cable.
Ive auditioned them A-B swap-out with a bevy of both high priced and mid-priced 3rd party offerings to this power cord. It is very well constructed and a fine performer , made by KLOTZ in Germany for REGA.
I stood them up against a bevy of $1000 power cords including OYAIDE , FURUTECH, ATLAS, ECOSSE, LFD , DIY with the top FURUTECH components , SHUNYATA and about another dozen in the $500 range including PS Audio, Audioquest blah blah
In all cases, tbe REGA was at least the equal and frequently actually better than all these contenders and pretenders...full stop.
my take: If your new REGA gear has the same power cable, just forget the fear and paranoia of thinking that a new 3rd party will get to a new perform level. You are wasting your money.