The peace garden appears on the park maps but I failed to find it when I first looked possibly because I was maybe expecting more. It's still a war memorial and it is somewhere peaceful to go in the park.
The co-ords take you to one of the entrances. On the floor is a plaque which starts "Commemorating..." Take down all the numbers in order. Then move on to the next plaque by the bench and then the final one further down the path. Still taking down all the numbers in order. Use them to find the find co-ords.
AB CDEF GHJK LM NPQR STUV
N51 27. S-G F-V A+B
E0 7. M-N P-T K+U
You won't need a hint to find the cache but if you do want one then at the plaque by the bench count and use the letter at that position, 20 7 17 4 34 33 13 37 10 31
***** PLEASE NOTE IMPORTANT *****
CACHES ARE NOT ALLOWED TO BE PLACED ON ACTUAL MEMORIALS OR WITHIN THE BOUNDARY OF SUCH
AT ALL TIMES PLEASE TREAT LOCATIONS OF MEMORIALS WITH RESPECT