Chances are a 900mm thick stone wall will be rubble filled .
Many thanks, sounds fun, it is Sandstone as most cottages up here in Scotland are built.
If the wall is filled, just go at it from both sides (you need to measure accurately though)
No,or use a long drill to make a pilot hole as a guide ( it may get deflected by a hard stone )
finally some sense.Dismantle the fascia stone (enough to be able to work) carefully and preserve. Hammer out the hole. Pipe through and re-build from the inside out.
finally some sense.
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.
Are you a trade or supplier? You can create your listing free at DIYnot Local