Unknown condition makes the price the key variable, but at £1,600 this is a strong deal: it sits below the £1,625 25th-percentile figure from six recent comparables, and well under the £1,834 median. Assuming it is complete and working, that is bargain territory rather than merely fair pricing.
The MPS-2 is a serious, quiet, high-current supply built specifically for compatible Bryston preamps and phono stages, with four outputs, substantial filtering, trigger facilities, and protection circuitry. It can be particularly worthwhile if you already own a BP-26, BP-2, BP-1.5, BP-20, or BP-25 and need the correct supply, though it is not a universal upgrade or standalone accessory. With condition unknown, confirm the mains voltage, output cables, and operation of every channel before buying; if those check out, this looks like an excellent opportunity.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.