There are two quite different roofing jobs in Lutterworth and it is worth knowing which one you have.
The older housing in and around the conservation area is largely slate, on cut timbers, often with valley gutters and parapets where a Georgian frontage was added to an older building. Those details are where the water gets in. A parapet gutter that has been patched for twenty years will keep failing at the same place until the lead is renewed properly, and no amount of sealant fixes it.
Post-war and modern housing north and east of the town is concrete tile on trussed rafters. The common mistake here runs the other way: a roof designed for concrete tile can generally take slate, but a roof designed for slate cannot always take concrete tile, because the tile is heavier. If somebody offers to re-cover an old slate roof in concrete without looking at the structure, get a second opinion.
Re-covering is the point at which the Building Regulations become involved, because replacing a substantial part of a roof covering triggers a requirement to look at insulation. We arrange the Building Control inspection for that and see it through to sign off.
In the conservation area the covering material is not a free choice. We check before quoting, and we quote the material that will actually get through.
There is more detail on coverings, flat roofs and repairs on our roofing page.