It's not just the amazing technology or unparalleled view from the air that provides such a jaw-dropping capability from a fast jet. The real magic is provided by the Imagery Analysts that can pick-out key information that cannot be replicated by anyone who has not undergone years of training:
I am sure it can provide an amazing images - but how useful are they in planning flood response and defence? Can the images be used to produce accurate topographical maps? Does the RAF even have the processing capability to make topographic maps with the data? Can the radar technology see through vegetation and map the ground contours underneath (something that LIDAR can do)?
My best guess is that it can't do these things as it was designed with different objectives. If it just takes detailed 2D images without rectification to a datum (e.g. WGS84) then I can't see it being very useful for flood response planning.
Lots of good
PR for the RAF though!