The seller says, "I don't know what size the wheels are" which is certainly affecting the interest.

+1 to look for used wheels locally.

I wouldn't limit yourself to 27" wheels, assuming you have enough reach with your brakes. There's about a 4mm difference in radius between 27" and 700c. If your break pads can move down this slight amount (usually not a problem), you will find many, many more tire options at 700c. I still use 27" wheels on occassion, but usually only because they are original and I'm a retro-grouch that way. In this case, I would recommend 700c replacement wheels if the original 27" ones are beyond saving.