Condition noted, this reads as excellent value: a fair benchmark for the PQS-402 in used market terms is roughly £23,000-£31,000, with stronger examples stretching higher, so £70,000 is a very substantial ask rather than a bargain. Against current new pricing around £87,000-£109,000 depending on finish, it is still below retail, but not low enough to feel like a used-market steal.
That said, the PQS-402 is a serious statement speaker: omnidirectional 2-way design, big-room scale, deep extension to 24 Hz, and high power handling, so a clean pair can be hugely rewarding if you want immersive, room-filling presentation. If this includes the original cables and accessories and has been carefully housed, that supports the value; with a speaker of this size and complexity, I’d mainly want confirmation on cosmetic condition, driver health, and whether the included extras are complete.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.