I expect Spain to be similar, in Portugal there are 4 or 5 bikes that hold value well: XT600E or XT660R, DTR125, any version of CBR600, any version BMW GS, Suzuki GSX750R, Hornet 600, any Africa Twin . These, except the Suzuki, were the top sellers of their generation, in a country where minimum wage would be (and is) less than half of the UK, buying a CRB600 was seen as buying a quality item that would last, like buying an oldschool Mercedes of sorts*.
*Except the DTR125, all those guys wanted was to put a motocross exhaust and wheelie to high heaven in front of high schools ?