The cache is not at the above co-ordinates and you should have noted letters and numbers in some of the rest of the series.
If you have, you should be able to work out the co-ordinates for this last one.
If you haven’t noted them we wish you a nice trip back round the series !
Unfortunately we've had to archive a few of the series, one of which had a number needed for this one. The missing information is e = 1
The bonus is at N54° (c–d)(b+c(.b(c+e); W001° (d-e)a.bc(a-b-e)e
Don’t forget a pen and tweezers might help but please replace the cache as found
Now that a few have tried these we can’t resist adding this - gratulantes, quod primae reperiunt to “alips” and “amyypow” jointly for almost all the series, except one - and to “Spud & Nugget” for “Plumb Round the Bend” as well as all the rest. Glad you all seem to like this little series, so more happy caching to all