Long cycle - Ashridge and Bison Hill

Set off at 6.55am on a beautiful sunny morning. The session was to be about time in saddle, I had 2 hours, I also wanted to practice the high cadence encouraged last week and keep the HR below 140 as much as possible.
Headed for Redbourn, then along the lane to Gaddesdon Row. Hardly any traffic and sunshine meant it was a tranquil ride. Headed down the hill to the Aylesbury-Hemel road, crossed over and began the first climb of the day to Potten End. At mile 10 this is a chug but easily doable in the seat.
Then it was down to Ashridge, again no one around except a family of deer which was sweet. Took on my fuel at mile 15 and sped past Ashridge College. Was reminded of the Berko Half Marathon in March which included this part of the ride, much easier in the saddle.
As I turned towards Whipsnade and the killer Bison Hill I thought I'd take it easy but the road is downhill, there was no traffic and I thought I'd go for it. 37mph wasn't bad.
Bison Hill runs up beside Whipsnade Zoo. It is the worst hill I know in the area. I tried to stay in the saddle but eventually was standing and working very hard. HR reached 170, which is about as high as it's been on a bike. After the hill it recovered well and was down below 150 within a minute. I wish that happened when I run up a hill, somehow I never recover on a run.
It was downhill to Markyate for the next 4 miles and I chugged along at an average 23mph. After Markyate the last hill is up to Slip End. Not as challenging as Bison Hill but at mile 25 its still draining. Cracked it and was happy to see the HR stay south of 160.
After Slip End it was the home straight on the A1081. It was now near 9am, the sun was hot and still the roads were quite. So I decided to push to the High Street at an average 21mph.
On arriving home I decided to through in a quick transition and do a 15 minute run, the legs found there form after half a mile and managed to hit the heights of a 7.15 mile. Stretched to finish and thought about tomorrow's 5 mile time trial with Running Fource. Mmm.