Hi, I am attaching a pergola to a concrete base, onto the slabs, which are council style, 50mm or so thick. I have this as the drill: https://www.screwfix.com/p/dewalt-d...-cordless-combi-drill/899cf?_requestid=366354 And this as the drill bit (14mm): https://www.screwfix.com/p/straight-shank-masonry-dril-bit-14-x-200mm/1550v?_requestid=366707 And it is hardly making a dent in it, and if I try and force it, it will knacker the drill I feel. I did drill one hole yesterday, and it took around 20 minutes, and tried another one today, and it is hardly getting past 1cm deep. Can anybody please advise, as the missus is now getting impatient and wants this pergola put up, and I cannot even get into the concrete for the holes. Thank you in advance.