Don't forget that your battery will get very hot from the Rapids and the rates for the 2nd and 3rd charges will be slower than the first Rapid. You will need to pause additional time at each stop to let you battery cool down - ideally with the bonnet lifted to help airflow. If this is a one day journey you can hire an ICE for around £30 from Enterprise and sit at the speed limit and not worry about your battery or having to be in with the HGVs and with similar fuel costs (a similar jouney for me in a hired Fiesta ST which I thrased on a cross-country rally route cost about 15p/mile - on Rapids it costs at least 10p/mile in the LEAF at a genuine 60 cruise - driven like the hire car it'd have been twice as much). To me a no brainer.Those numbers sort of suggest around 5% degredetion.
For the leaf assume 82 x 0.95 = 77 miles
At these temps no loss from cold. (1mile per every 4 degree F below 40)
X 80% for each leg after the first then minus 12 miles for plan B.
Knock off 1 mile for air con on your first leg
So 64 for the first leg and 50 for every leg after that.
As noted if you can do Milton Keynes you can prob do 70 miles as you don't need 12 miles for plan b there.
Don't use cruise control. Use the speed limiter instead.
*maybe the charging networks got better since last year and 12 miles is overkill?