She began with a grounding in in showjumping and was skilled enough to reach international level. Under the influence of her uncle Sir Edmund Loder - breeder of the great European champions Marwell and Marling, Harriet decided to move further more towards thoroughbred fields and worked at her uncle's Eyrefield Lodge Stud in Ireland. Subsequently  she was worked for several sales consigners preparing and presenting horses. 

Returning from Ireland, Harriet joined Richard Frisby Bloostock Limited in Newmarket, the head quarters of British Thoroughbred racing and breeding industry were she assisted the former director of the BBA (UK) at sales in tasks such as researching to sourcing potential purchases. 

In 2010 Harriet successfully graduated from the Irish National Stud breeding course where she studied a variety of specialist subjects including handling stallions in the covering shed, foaling and the management of forthcoming yearlings. More recently Harriet has been working independently but she has kept her strong links to the BBA and her worldwide clients, which include owners, trainers and breeders.

In 2013 Harriet purchased Marwell Park to be the home of Loderi racing and is now developing the stud to become one of Newmarket's premier stud farms & boarding facilities.