I'd say it would be £100 lower
There is a lot of this around, and not many 410s go for much above £400, so you can drop it for a 400?
The scope is good, but perhaps £150?
And I sold a 7L 300bar bottle last week with 3.5 years test for £120 - in 18 months the buyer will have to shell out £50 for a test, so I'd say £100 would be a decent deal?
These would be individual prices, getting them as a package is probably £50 less, so £600 - £650 I would have thought to be top money for what sounds like top quality gear.
Condolences to your family, and good luck with the sale.
James