Condensation issues end of Terraced victorian house

Insulation, ventilation, and heating are the main factors to take into consideration, over doing it, or under doing it, will cause the issues you are facing Please get in touch for a long term solution, each property is different, without understanding your lifestyle, it's very difficult to state the best long term solution for your property. I wouldn't recommend a PIV unless your property can hold minimum of 18-19 degrees celsius.

your house is solid brick built no cavity so air bricks are a total waste of time, bricks are porous, it was built with lime mortar which allows any water ingress to exit the building via the mortar lines, it has most likely been repointed with cement which will trap water ingress in the wall making them cold damp & creating a high humidity in the property this will allow any condensation created in the property to condense and create mould, a site visit would be required to see what the best long term solution maybe, modern materials and old houses do not work well together as they are trying to achieve different things, most modern damp proof solutions are designed to cover up rather than solve the issue, dampness dissipates at the rate of 1 inch per month as its a nine inch brick wall it would take 9months for the wall to dry out fully without any further ingress through weather or living conditions, while a piv unit will allow air circulation in the property without finding out were the water ingress is entering the structure it will not solve the problem long term. good luck Alex