The 5 Charater PNR is the CX CUPID system PNR. It is different to the Amedeaus system BA/QF uses. HOWEVER if you ahvea QF/BA sector after the CX one, they might have an information booking on the BA/QF RELOC/PNR so check it up and see.
If u want to see the seat map u can do a dummy booking on CX.com and you can then see the seat map just before u pay for the ticket