Looking at the price of a new pump they seem over a grand....Is there a competitive replacement for the one I have?yes you can get service kits but it isn't really worth it TBH. @ 17 years old, lets be honest, it doesn't really owe you anything. Time to send it out for retirement and get a younger model in methinks. Even if you replace seals etc there's no guarantee something else won't go.
At least, some of the pipe runs are probably 25 metres.Presume nothing, check everything is the way I work.
Do you really need a 3bar pump?