N.B. Puzzle formula changed in July 2022
To find the answer to this puzzle you will need to determine the link between the names of the caches in the Steep Marsh series. The cache is not at the co-ordinates listed but you may very well find some inspiration there instead.
Once you have worked out the link, you can find the Puzzle Cache at N 51 01.ABC W 000 55.DEF, where:
| A = |
Ebenezer Scrooge - T E Lawrence - 6 |
| BC = |
Flintwinch - 30 |
|
| D = |
(Oliver Cromwell - Queen Victoria) - 13 |
| EF = |
(Wicket - Pip) + 1 |
If you follow the route highlighted below from #7 Oliver Cromwell back to the recommended series parking at Steep Church, you will pass the final locations for the three bonus caches and the letterbox (with some small detours obviously).

N.B. The pub toward the end of the route is old, does great beer and food, but does shut in the afternoon and only accepts cash.
For ease of reference the caches in the Steep Marsh series are as follows:
[For the Puzzle] Gjb qrterrf bs frcnengvba & JVLS
[For the Cache] Yrsg unaq fvqr nf lbh nfpraq. ZGG oruvaq ubyyl.