This looks fair to slightly strong, not a bargain, for an AV40 at £1,613. A clean boxed example has recently been listed at about £1,750, so your asking price sits a bit below that level; for a processor that originally carried a £4,399 RRP, this is still firmly in the realistic used zone rather than an eye-watering ask.
The AV40 is worth buying because it’s a proper high-end cinema processor: strong feature set, very capable decoding and room correction, and the sort of platform that makes a serious home-theatre system feel complete. The main upside here is simply getting a premium processor for much less than new; if it’s complete, recently tested, and includes the ARC setup mic, remote, box, and cables, that adds real value. If condition is unknown, I’d just confirm firmware, HDMI stability, and that all channels pass cleanly before paying full ask.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.