Thinking back almost 20 years to when I was swinging a hammer and cutting holes in roofs, installing flashing etc (in London even)...I'll not offer any advice without seeing what the problem is.

But, I will caution you on one thing. I, personally have no fear of heights, but one thing that seems to be a law in the roofing community is that everyone falls at least once. The only thing that changes is the height that the person falls from, but everyone I've ever known working up high has fallen. For me it was only 10 feet, but sonemone I know fell 20 feet and was laid up for a year. An ex-para guy who kept going for a rip cord that wasn't there as he plummetted


So be very careful and if you don't know what you're doing on a ladder then take extra special care.