Hot water takes a long time to reach the tap/shower?

My boiler seems to work OK, however, it is a little old, it's a Potterton Combi 80), which is no longer in production.

When I turn on the hot water tap in the kitchen the hot water takes approx 1 minute to get to the tap... in the bathroom/shower it takes longer, although these are further away and upstairs. The kitchen sink is approx 4M from the boiler... I do not know the route the pipes take tho, as it was all in when I bought the house 5 years ago.

Could this be that boiler needs descaling? Hot water pressure is good, both downstairs and upstairs, so I don't think it's the pump...

Central heating works fine.