Always a bold move to place yourself in somebody else's hands when it comes to planning a walk. All the more bold when your guide is one of those sans-map, winging it kind of sporty types who believes they can just excavate their way out of any trouble with a bowie knife (avalanches, broken legs, earthquakes, difficult to open tupperware boxes, etc). Never trust a walker who doesn't wear socks: never trust anyone on the tops!
So I can't say for certain the route I traversed, but I know we started in Grasmere, passed Alcock Tarn, and headed up the first half of the Fairfield Horseshoe at breakneck speed. I just wasn't fit enough and pegged out a couple of times on the way up, not that Buzz Lightyear was bothered, having trotted off ahead by a few furlongs. Although I had (literally) done the hard yards and managed to ascend Fairfield (the rest being ridge walking), I was just in shreds so we took a turn east and descended back to Grasmere along a reasonably pleasant path not pictured below (if only I had been in any fit state to enjoy it). By making the impromptu descent I think we carved about 8km (5 miles) off the intended walk for which I was existentially thankful. This is only the 2nd walk I have had to cut short in my life, but it does show you even experienced walkers are not invulnerable and emphasises several time-honoured rules:
1. Always look out for your buddy, tracking back if you have to
2. Always have a PLANNED off-ramp (escape route) off the mountains and don't be ashamed to use it.
3. Even if you are fit enough to accomplish a walk, be prepared for the unlikely event of becoming unwell or incapacitated. Even a twist of the ankle can quite radically change the calculus of a walk.
4. Tell somebody who is not on the walk where you are going and an approximate time of return.
5. Keep your mobile charged.
Stay safe!