The thing is that "transco" are primarily an emergency service and not a provider of metering services.
They do however carry out meterwork under certain circumstances..
1) If they are engaged by a meter asset manager to exchange/install/maintain a meter. n this case the MAM pays "transco" for its work.
2)If the meter,inlet flex or regulator is leaking ,then "transco" can exchange the faulty bits as long as a contract exists between the MAM and "transco" for that work to be done..otherwise they just cut off and go. Contracts only exist for meters upto G4/U6 size so anything bigger just gets cut off and left.
So then,if you ring "transco" and report a gas escape when there isnt one,with the intention of getting a meter refixed or an outlet flex removed or a lead inlet removed...then they are not obliged to do it. Approaches for non emergency meter work should be routed via the customers gas supplier.
Lead inlets and/or flex outlets are permissable if they are existing and can be left in place. "transco" do not replace them unless they are undertaking meterwork i.e new fix/exchange. There is nothing to prevent a GSR from running a new Cu supply from the meter.
HTH