It's hard to be certain because Streetview doesn't work on that part of the street, but based on no. 47 being next door, I think it's probably this house:
https://www.zoopla.co.uk/property/uprn/100021161879/
Which Zoopla thinks is worth 981k to 1.2 million.
From Property Log on Rightmove:
Burgoyne Road, Haringey Ladder, London, N4
Offers in Excess of
£1,000,000
Price Change History
09/01/2024 Price changed from £1,250,000 to £1,000,000
17/11/2023 Price changed from £1,200,000 to £1,250,000
16/11/2023 Price changed from £1,250,000 to £1,200,000
30/10/2023 Price changed from £1,350,000 to £1,250,000
09/10/2023 Initial entry found: £1,350,000
Overall change: -25.9% (-£350,000)
If you look through the photos, it was almost as bad before they moved in.