I have used Dryzone very successfully to treat rising damp (and it certainly complies with BS6576 as it has BBA and other certifications). Obviously it will only work if the source of your problem is indeed a defective DPC.
Thompson's Waterseal is effective against rain penetration as long as you deal with any faulty pointing or cracks in the masonry. It is stearate-based so will only last a few years as it will get broken down by sunlight. If you want a longer-lasting product you would have to use a silicone-based waterproofer which would cost a bit more.
Thompson's Waterseal is effective against rain penetration as long as you deal with any faulty pointing or cracks in the masonry. It is stearate-based so will only last a few years as it will get broken down by sunlight. If you want a longer-lasting product you would have to use a silicone-based waterproofer which would cost a bit more.