Amstrad 464 plus + Amstrad Monitor & Games [still in box unused]

Hi there my names Marco & my Grampa, Remo Agostini used to own a computer shop at Craigshill Mall in Livingston, Scotland around 1982.

He has some old retro machines he is looking to get valued.

They have been stored in his loft for many years since his shop closed.

The item I'm really looking for a valuation is a mint condition still in box Amstrad 464 plus that's never been used.
He also has a mint condition Amstrad colour Monitor & games still in brand new condition unopened.

I was wondering if you know the value of the Mint condition Amstrad 454 plus +games
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