I wouldn't touch Everest with the proverbial 'shxtty stick'. Excessive 4hr sales pitch, expensive, roof thrown up in a day, leaked for 2yrs, took them a year to escalate the problem to the engineers (prior to that they just sent fitters - once a month!!!). Even their own contractors (yes they don't employ their own staff!) Slag them off. Eventually stopped the leak but it's a very poor installation, bit missing sharp edges etc. Save yourself the money and go with someone local. Their 'Fit The Best' slogan couldn't be further from the truth. Avoid like the plague