We are in the process of buying a house that had a single story extension about 6years ago. Full planning was permitted but no building reg certificate was obtained. The current owner has a indemnity insurance in place, so no major issue on that score. However, we intend to extend above the extension. Therefore once we get the planners out I'm assuming the indemnity will be invalid...however we will get building reg certificate once extension is done. Just wondered if anyone else been in this situation. Will the planners want us to get retrospective building regs for single storey extension before we start on second storey.(subject to planning).

We don't want to ask vendor to get retrospective building regs as this could invalidate indemnity which maybe a problem with mortgage company. Any thoughts appreciated.