The 240 foot high receiver towers were built of wood, to avoid interfering with the weak received radar echoes. The concrete bases of these wooden towers were larger than those used for the transmitter towers.
From its location this must be the R-block, but it doesn't look as it would have done in WWII. It would have been surrounded by a blast wall, on the outside of which would have been piled up earth. This blast wall seems to have been taken down and the grassy piles nearby suggest what happened to the earth. I think the top third of the building's height, indicated by the different coloured brickwork, would have been filled with gravel in an attempt to limit the damage of a direct hit. Originally I think there would have been fewer windows in the block.
Peter Facey, Winchester, England
20151017 originated