HM Land Registry records the plot of land for 20, Mardley Avenue, Welwyn as measuring 915 m².

That makes it the 4th largest plot in the postcode, where 12 of the 13 other houses have recorded plot data.

The most recent sale of 20, Mardley Avenue, Welwyn completed on 20th January 2006 at £332,500 and was recorded by HM Land Registry as a freehold house.

Since 1995 this is the property's only sale.

• Sold Jan 2006£332,500

Over the past 2 years 1011 properties have sold within 1.3 kilometres of 20, Mardley Avenue, Welwyn, per the Land Registry and our network of Estate Agents.

The latest, on the 12th December 2025, was 1, Rosecroft Lane, Welwyn, AL6 0UB, a freehold house which sold for £775,000.

Read more about house prices in AL6.

• Sold Dec 2025£775,000 | 4 Bed House1, Rosecroft Lane, Welwyn, AL6 0UB1, Rosecroft Lane, Welwyn, AL6 0UB
• Sold Aug 2018£690,000 | 4 Bed House16, Mardley Avenue, Welwyn, AL6 0UD16, Mardley Avenue, Welwyn, AL6 0UD
• Sold Aug 2017£665,000 | 5 Bed House18, Mardley Avenue, Welwyn, AL6 0UD18, Mardley Avenue, Welwyn, AL6 0UD

•Nearby is defined as the radius comprising the nearest 2,000 addresses.

• St Michael's Woolmer Green CofE VA Primary School

  700 m away
• Oaklands Primary School

  800 m away
• All Saints Church of England Voluntary Aided Primary School, Datchworth

  2.1 km away

• Monk's Walk School

  3.3 km away
• Ridgeway Academy

  4.9 km away
• Barnwell School

  5.0 km away

• Knebworth

  |

  2.4 km away
• Welwyn North

  |

  2.5 km away
• Watton-at-Stone

  |

  4.8 km away

The flood risk here is rated Very Low, based on Environment Agency data.