**N 51° 42.902 W 002° 41.262**

A bit more of a trek to this cache on this morning’s expedition, especially as I needed to divert around a bit of the path that had flooded and become impossibly muddy, at about N 51°42.902′ W 002°41.262 (added as log coordinate).

Found the cache without difficulty (nice to have on a little bit off the track, too: had to hop a brook to get here!) and tried to work out the location of the bonus… but discovered to my horror that I’d somehow got only 9 numbers written on the back of my hand; not 10 as I’d expected. I realised to my horror that I must have forgotten to write down one of the numbers from one of today’s caches! (There might have been some swearing at this point in my expedition.)

But, I thought: I can probably work it out! My first five digits (which I collected earlier in the week) must certainly be correct. So it’s only the last five. Of these, the final one I *knew* must be the final (least-significant) digit, because I was standing at cache #10 and I could see it, so that meant that I had three digits to put into four possible positions, and one unknown digit to put into the gap… how many permutations could there be? And it’s simplified a little further still, because I know that the missing digit can’t be a 0, because there’s no way to express that using playing cards… and I knew that if the missing digit was the one from cache #6 (the most-significant unknown digit of longitude) then there was an even more-limited number of possibilities (or else the cache would be further away from the series’ recommended parking spot than the distance stated in the description)… I was already running late and didn’t want to have to double-back, so I started coming up with permutations of digits at which the bonus cache could be! Once I found a likely candidate, I set off for it… but would I be correct?