What makes winter roof prep in Newmarket unusual is not the technique, it is the age spread of the housing: a single route can cover 1910 brick and 2019 factory-built venting.
Infill and renovation work in Newmarket frequently reroutes venting without re-sizing it, and undersized or over-long runs are the single most common cause of poor draft we see.
Range hoods and basement bathroom fans routinely out-pull an older flue, so the house depressurises and the flue reverses — a Newmarket problem that looks like a chimney fault but starts elsewhere in the building.
Across Bristol-London, Central Newmarket, Glenway Estates, Gorham-College Manor and Stonehaven-Wyndham, the housing stock changes street by street, and the correct method changes with it. A century home with a soft-brick stack does not get the same treatment as a 2010 build with a factory-built vent — using one method on both is how systems get damaged.
the practical takeaway is that a winter roof prep visit should start with an assessment, not a tool. Any crew that begins work before telling you what they found is guessing on your behalf.