Where can I buy nails that go into concrete I do not mean masonry nails as they do not work but special nails that bang into concrete I have some now so I know they exist. UK?

Masonry nails that depend on a powdered charge for their penetrating force should be available at home centers or lumberyards. As a last resort, google powder actuated nails. An alternative is to use Tapcons, threaded concrete screws which require the use of a predrilled hole for ease of entry. They work very well.