Window and door specialists supply and fit windows, exterior doors and the sealing and trim around them. On The SteelToe App you can find window & door listed by town, with phone numbers, free and without an account.
The work covers replacing failed or draughty units, fitting new openings, repairing rotten frames and sills, and glazing repairs. Much of the performance comes from the fitting rather than the unit: a good window badly sealed will still draught and leak.
Ask what happens to the old units and whether disposal is included. Ask how the opening is made good inside and out, since trim and plaster repairs are often excluded and are visible. Ask about the energy rating of the glazing and whether the quoted unit matches what is on the paperwork.
A broken window or a door that will not lock leaves the building open. Board it up if you can and call for a temporary secure fix, which most firms will do ahead of the permanent one.
List your business free. You get your phone number, your website, the towns you cover and what you specialize in, plus an ordinary followed link back to your own site. There is no charge when somebody calls you.