Mike,
Frederick Jacobson is listed as a "hat & cap" maker in the Post Office Trades Directories 1891 and 1899. I did not find him in the 1904 directory but then again I didn't find any of the usual suspects either. I reckon the date as being 1891 from the maker's stamp inside your helmet.
I do not think that any British regiment wore a 4-seam foreign service helmet but we do know that Colonial and Dominion forces did. See attached for the Queensland forces c1886.
It is likely that chinchain rosettes were used by the British but very rarely and probably at the Colonel's whim. I do not, however, have any reliable information on this.
The high-hook is of the "hook and eye" type readily found on tunics/mess waistcoats etc. but was used in place of the "bolt through" type. These were stitched to the interior, is yours? I also notice that there are two indentations on the exterior of the helmet where the ends of the hook would be inside. The hook itself seems to be bent back but that is of no real concern.
Given the above I would say that the helmet plate to the West Surrey regiment is a later addition, possibly replacing a missing Colonial plate.
Hope this helps.
Stuart

- HELMET 4 SEAM QLD.jpg (310.52 KiB) Viewed 347 times

- HELMET 4 SEAM QLD description.jpg (146.93 KiB) Viewed 347 times