Your own coin Rob is not the same as Ians which is Bisect BP1898Ca and much rarer, yours is Ba. Although i agree not the easiest coin to sell Ians is probably worth about £80 if he can find someone that wants one, obviously he can asks what he wants its just finding someone that wants one and priced any higher may have it a while.
Nice coin, but not particularly rare. Lovely history concerning their minting at: https://en.wikipedia.org/wiki/Eloy_Mestrelle
In that condition probably £80 to £100. At least is appears to be genuine - there are fakes around.
Here is mine - slightly better condition: