usually, "Rising Damp" is a chimera.
Google "Rising Damp Does Not Exist" and see who says so.
Chemical injection is fairly useless.
If there is damp, there will be a cause. The cause needs to be identified and corrected. A wrinkled local builder will be familiar with the common ones
e.g.
Earth or paving heaped against the side of a house raising the ground level above design height
Airbricks blocked
Paving sloping towards house leading rainwater to run towards it
Water leak, maybe under or in the floor
Dripping sink waste
Broken drains
Incompetently laid solid floor
Less common ones include house built on stream or side of hill that water runs down.
Whatever the cause, it has to be identified and corrected. Damp Proofing companies will tell you that you need to buy their damp proofing treatment, but if the cause is one that I have mentioned, it will not be cured, and careful reading of their guarantee will show that it does not guarantee against such causes and a recurrence of damp.