I have the same problem and have just come across this: -
Not tried it yet, but it has excellent write ups.
Also, importantly for me, it claims it is breathable.
Another point is that it seals the brickwork against staining. This is also very important to us as a couple of our exposed walls are in our kitchen.
We have exposed some Georgian walls, raked out the old cement mortar back down to the original lime mortar and repointed using lime mortar.
Being mostly Georgian brick,