think your consultant being extra cautious, evening primrose oil fine, all natural no reason it should give you an infection.
plus midwifes etc actively encourage sex to help bring on labour, unless of course you have had bleeding or your waters have broken, once waters have broken you dont want to do anything that might be an infection risk obviously.
but my waters are intact so baby happyily contained, i have two close friends who have done the evening primrose oil thing and from what i have read it is quite a common way of helping cervix to get ready, the chemist had even heard of it and said 'ah i know what you will be doing with these' when i bought them 
FENN fab that little one has sorted his tongue out, hope feeding gets easier, and i cant believe they wouldnt cut it, mind you my local hospital doesnt either, i would have to travel to Ipswich if the baby turned out to have tongue tie, the boys were all fine tho so hoping madame will be too.
i am another one that wont dare try castor oil, already get bh's which give me an upset tummy, NO way to i want the runs from castor oil!