He seems to have been a Grundig enthusiast, there are plenty of Satellits and cassette recorders to go round.
https://i.dailymail.co.uk/1s/2020/10...2060248308.jpg
That's the only radio equipment I saw while scrolling through a lot of photos, though there is a mountain of Electronic Engineer-type kits. I can't imagine what justifies the valuation, unless there's a large quantity of signed memorabilia. The pile of "rare books" shown resembles the stock-in-trade of any modern market stall.
Paul