Marshallswick didn't disappear at all - it merged with Wheathampstead School in 1988 and became Sandringham School. I personally would not advocate living in Harpenden at all as it is full of Nouveaux Riches and very snobby. The house prices there are generally ridiculous! (although there are a couple of really good secondary schools there). If you don't want to live in the middle of the town, the surrounding villages are nice - Wheathampstead (if you avoid the estate) and Sandridge are lovely as are Redbourne, Gustard Wood, Kimpton, Whitwell, Lemsford etc. (but house prices in all of them are high). I would avoid Hatfield but Welwyn Garden is really nice (although there are bits to be avoided). Hertford is lovely (in the top 10 places to live in the country) but it is quite a commute to St. Albans.