Before buying replacement speakers, I would try to find out if all drivers are "blown" or just the HF driver, one or more of the mid bass drivers or the crossover. Those are probably still available from B&W and are easily DIY replaceable. Won't be cheap but cheaper than a new or used set of replacements.
I also agree that although the 2270 is iconic, unless it has been significantly re-built, it is 40+ years old and prone to have failed components. I would take it out of your audio chain and stick with the MAC, exclusively. If the 2270 is only being used as a tuner, no offense, there are better vintage tuners out there. Having sold those receivers in the late 70's, the amp and preamp sections were the standout performers of the units.

