Orlit houses are made of precast reinforced concrete (PRC). Over time, PRC deteriorates, particularly at construction joints and junctions between components, with a gradual reduction in structural effectiveness. Also, this material often suffers from inadequate overall thermal insulation, as well as thermal bridging and subsequent condensation problems. In Scotland, the Orlit house type was designated as defective under the Housing Defects Act 1984. Most of them were built in the UK during the 40's and 50's postwar period as a quick and cheap solution but the majority have needed major repair work or have been demolished since. Most UK lenders won't give any form of mortgage for them at all, so you're lucky to be able get 70% here, but I'd recommend to forget about the house entirely and look for something else. If you really want to go for that house, make sure you engage a good surveyor who is very familiar with these house types before you decide.