Having been travelling up and down the ECML regularly for several decades now, and also driving regularly on the (old) A1 which is adjacent for the majority of the route, I've written up my own 'guide' and identfied some of the smaller buildings (chapels, formr stations, manor houses etc.) that are visible. I'll send a copy to the OP by PM when I get round to it.
Now I don't know about that number, but your question reminds me that there are some fine follies to be seen : Belton House library at Grantham positively glowing in the midsummer evening sun, or Ratheugh Folly at Alnwick shining in the early morning sun; then there's some notable modern buildings : Sarah Wrigglesworth's insulated Eco House in Holloway, or the Eton Lakehouse repro deco house at Arlesey, and then there's estates built in fiddly detail such as Victorian gothic Pepper Arden at Cowton or the empty Scottish gothic Ayton Castle at Burnmouth, and then there's the many converted windmills, some only just visible such as the pointed Spindlestone in Northumberland, as visible as the point of the Knights Templar's chapel at Temple Hirst jn..
Then there's the twists and turns of the track, the wavy Offord Curves between the Great Ouse and the Offord churches, the changes of direction at Ayton, Hett and Aycliffe, or the range of utility infrastructure, including the unique cats-head pylons at Tuxford and every conceivable shape of watertower.
One sight that makes me smile is the brickwork of the Balby Road tunnel at Doncaster which has been constructed with big curved holes to allow the red sandstone rock to poke through!
Just don't get me started on the continuation to Inverness!
