I was surprised when I looked that there was no recipe for roll mops on the site. A grave omission! So here is my version. Other fish can be used. I have seen versions for trout fillets but herring is still the traditional fish to use.
You can use four whole herrings and fillet them yourself, if desired.
I use red wine vinegar but you can also use cider vinegar as an alternative.
The strange implement in the photo is an old gadget that was used to make a single cup of tea back in the days before tea bags were invented. Mine was given to me by my mother and I don't think they're available these days. It makes adding spices to a mix so much easier. The alternative is to just add the ingredients and then sieve the vinegar before use.
Step 3 is confusing. Do you add the 450ml of vinegar, or is it 450ml of 'water and vinegar', in which case what proportion? Is it 450ml of vinegar and some water, in which case how much water? - 17 Dec 2014
Just a note about your "odd implement" While I have never seen them in a spoon type shape, "tea balls" which are essentially just a small, hollow, ball of metal with holes in it....used to make tea with loose tea, are quite easy to find at least in north America and usually cost all of about 2 dollars. - 29 Nov 2013