Valuation please

[BAD DAZ]

Hi peeps, sadly after a short battle with cancer, my uncle Geoff passed away, some of you have met him at the Springer bash and even bought stuff from him. His wife has asked me to sell his set up as she has bills to cover, as i know nothing about PCP guns, im going to need some advice, he had recently purchased a new AA s400f .177 single shot, he zeroed it in and then put it away, it has probably shot less than 100 pellets, it has a Hawk panarama 6-18×50 scope, silencer and a 7 ltr bottle with 18months left on it. I have no idea what this set up is worth, but it would be ideal for someone just getting into the sport, so if you guys could give me a ball park figure, that would be great, atb Daz