As the mortar will be more sandy than the rest. you could run a bit of filler across it and sand it down smoother afterwards. Then bit of PVA sealer before appying paper
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