Personally I have no plans to get an airline job. It took me many, many years to get a colour-vision restriction removed from my medical, and times have changed. I can no longer feasibly afford to take the pay-cut that a FO job would entail and still pay my mortgage.
I do however have my own (SEP) aircraft, plenty of instrument time, and am in the process or getting the IR for Class A access and international touring. I will probably do the 15hr conversion as opposed to starting from scratch within a regulatory framework which says my instrument time counts for nothing.
The IR can be completed on your own aircraft providing you get it approved. This essentially means getting some screens made up. Despite the cost savings of using one's own aircraft, the instructor hire costs in the UK are astronomical, hence the Spain connection...