Convert regular/open to closed system boiler?

[OscarandLucinda]

Has any body done this and can advise roughly how much the extra labour cost and if worth it?
House not suitable for a combo boiler; engineer has recommended converting to a closed system as then some of the parts would be within the boiler itself and therefore covered by warranty, wouldn’t have to top up the tank etc
But the price seems to be 500-600 more than for equivalent straight switch - wondering if generally worth it?

We have a closed system, installed by the previous owners.
We are in the process of getting the bathroom re-done, and the 3 people who have been out have commented that we will have no issue putting in a shower, as we have "the best type of system".

Not sure that will help at all, but the bump might get someone who can actually answer your question!

Thank you - that is helpful!