Can't another vessel (about £25.00) be plumbed into the system at a convenient point eg cupboard underneath or a rectangular vessel on top of the units.
This boiler is old, often the flue has to come off, you need sufficient height above the boiler, and it could end up leaking everywhere and some boilers have to be taken off the wall to replace expansion vessel (and the manufacturers part may be obsolete or a rip off price).
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local