If you want a blunt and honest opinion, you're A-levels are far from appropriate.
Medicine is an extremely competitive field to get into and although "MINIMUM REQUIREMENTS" state your opinions are "TECHNICALLY FINE", there are a sheer amount of people that exceed these. Usually 3 sciences is competitive (as in Chemistry, Biology, Physics OR Maths). The fourth subject should really be a respected subject (Philosophy, History, RS, MFL, Latin, Further Maths, English LIT etc) OR take a fourth science.
4 sciences = Strong candidate, strong at sciences, will be appropriate and suitable for most unis, apart from UCL and Peninsula who 'prefer', not demand, a contrasting subject.
3 Sciences + respected contrasting subject = Just as strong, shows versality, will put you no great advantage or disadvantage from 4 science candidates.
Home Economics - A complete and utter doss subject, no real skill, no real respect AND a medicine candidate should never be studying it as it gives the impression you're very non-academic and not suitable for such as demanding and complex career.
Psychology - this is somewhat acceptable for your fourth subject, but, unless you have a raging 'passion' for it, don't take it and go for more academic contrasting subjects.