Hello - there are a couple of surveyors on here that will hopefully come back to you - but, in the mean time:
- You may be able to find this information on your Title Deed (using the date of the first transfer or lease by the original builder) or the Land Registry digital archives;
- Check the "Property Information Form" during the last sales process;
- Your local council may be able to let you know when planning was initially granted; or
- Talk to the local library/history society who should be able to check census data dating back to the 19th century.