Argos /Index catalogue do an SDS rotary hammer drill (including set of drills and chisels-unlike the screwfix one) for under £30.
From experience I can recommend these to the Diyer.
My local hire shop wanted £25+VAT for one.Buy one and then throw it away after 2 days and youre still in pocket!.I can get about 5 months HEAVY use out of them.They will put a 20mm drill through a stone wall in seconds.
If you have resounding ,long lasting,success with your dpc injection,and I am genuinly sorry to say,agian from past experience, I dont think you ever will, you will have wasted your time if you replaster with normal plaster as it will draw salt,which attracts moisture,which gives you the damp.
You MUST use a "Limelite" renovating plaster.It doesnt contain the salt leaching element.It is expensive but it works.
I would go as far as to repeat what my building inspector said to me(to the chagrin of the damp proofing industry) that removing the lower 1 metre of the existing plaster and refinishing with limelite would sort out rising damp without any DPC injection.
Ues the links masona has given to eliminate penetrating damp.