On ebay (https://www.ebay.co.uk/itm/used-toyota-mr2-seats/292749395405?hash=item44293945cd:g:tN4AAOSwbehbrz3V). Black/silver - not pristine but currently at £20 might be useful to someone if they are in that locality.
Also - hasn't done the best job listing them so may not get much interest. Including the words 'Roadster' and/or 'Mk3' would probably generate more traffic.
interesting - they were FL too, but I don't think that silver centre section wears very well, so not surprising that they only end for £25.