In one word - yes.
Since you were taught, ski equipment has changed substantially, and it's unlikely that you'll just happen to stumble across the new techniques unless someone shows you.
My suggestion, book a couple of private lessons, with some practice time between them, so the teacher can work with the skills you already have.
Many good UK skiers who want to keep on improving have tuition with folks such as Warren Smith or Snoworks, these events do tend to be quite intensive. Warren Smith is running tuition at indoor ski slopes across the UK this summer.
I don't work for either of them, and I've never been on either company's courses, but they do seem to have a good reputation, among people I've spoken to.
I have been on a number of 1-2 week intensive ski courses and consider myself passably competent, though other posters on J2ski may wish to disagree
