http://www.ebay.com/itm/Derby-Crown-Porcelain-Gilt-Canary-Yellow-Vase-1887-pre-Royal-Crown-Derby-9-3-4-/191047373966?hash=item2c7b4f948e:g:HH8AAOSwpDdVgIgb

Here is one on Ebay with the same mark as yours !! The small mark at the bottom must be the date mark because this is identical to yours and is dated 1887,, so I was not far off with the time period !! Keep in mind that the selling prices are not always the same as the asking prices !!

https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=royal%20crown%20derby%20vase&LH_Complete=1&LH_Sold=1&rt=nc&_trksid=p2045573.m1684

Above are the latest selling prices !! This is what people are actually paying for similar vases !!
I would try Ebay for selling them !! A pair usually sells better than a single piece but these and other decorative items have not been doing well lately !!