Get it serviced.
Get a Worcester Bosch service contract in place to do it. That gives you an annual service and repair cover.
A service contract can be VERY worthwhile
I had a Worcester Bosch combi at the old house that developed a small leak. Engineer arrived, sorted it but found another leak that had been caused by - and masked by - the first. Initial reaction was it needed a new heat exchanger £500 just for the part. Plus fitting. All covered by the service contract (phew).
In the end, it wasn't the heat exchanger but something quite sneaky, though an easy and quick fix.
Upshot was we had a brand new heat exchanger and the boiler fixed, all for nowt.