You'll be fine. I scraped through A level maths with a B (and no physics either), and did fine on a MEng course at a top 5 uni. As long as you're prepared to put the effort in, you've no need to worry!
Also, if the uni is prepared to make you an offer without a Physics A-Level they should bring you up to speed on what you need to know in the first year - you'll just have to work a bit harder than people with Physics!
Also (and without wishing to offend anyone) I found the maths associated with civil engineering easier than mechanical/electrical (at least in the first few years). This is probably because most of the calcs you will do will be static (you don't worry about time, if that makes sense).