I am trying to find out the name of this film. I think it was made for TV in the 90s. Plot summary- husband and wife hire a babysitter. The babysitter is quite plain looking and so the wife treats her to a makeover, but this makes the husband fancy the babysitter. The husband and babysitter begin an affair and slowly try to poison the wife to get rid of her however in the end the wife managed to poison and kill the babysitter and the husband gets sent to prison. Please help!!

Sounds like Perfect Alibi (http://www.imdb.com/title/tt0114114/)

You are a legend!! Thank you so so so much that's it! I've been searching for two days! Xxxx mwah

You're very welcome.