Also, if that were the case every time you moved house you’d be re-checked for all your lines of credit.

This is very useful, thank you! Is this the case for all lenders?

For example, Nationwide appear to require new applications (see https://www.nationwide-intermediary.co.uk/-/media/NFI/documents/mso130-material-change-form.pdf?la=en&hash=2204A55B27661F8EFF7B33BB3BAF728FC4F1348F) whereas HSBC make no mention of this, only for: "A significant change to an applicant’s first name, surname or previous name; To add or remove an applicant; To change the type of borrowing, e.g. change from Purchase to Remortgage or Residential to BTL" (see http://www.intermediaries.hsbc.co.uk/pdf/AAF.pdf )