Say they go for high estimate and do not exceed it. Add 20% (£2400)commission plus 17.5% VAT on commission (£480) and you have a total cost of £14,880. That is £7440 per gun.
The re-stocking will reduce their value. Then of course, it depends on the quality and style of the re-stocking. Bore measurements are not yet known.
So, assuming everything works and not a lot nees doing to them - you have a decent non-original shooter for a little over £7000. They could go for significantly more than the top estimate if they are actually very good - bringing them closer to the upper estimate of £10,000 a piece that Rocketman and I hit on as a realistic budget.
