Wel done lozzy - just keep at it - sounds like he is at the very least interested and not scared of the new food - just keep at it and maybe one day soon he will try something new - the other thing is just to put tiny bits of the new foods on his plate, so that it doesn't look overwhelming to him - it depends on the child of course, but what we did and still do sometimes with our youngest is to say to him that he cant have something because he is not grown up enough. Despite being a very bright 7 year old (he wants to be a judge and already reads at the level of a 10/11 year old), he still falls for it every time - he hates the thought of not being grown up, we know which buttons to press!!! We have gotten him to eat all sorts with that, the latest being stilton and celery soup.
The trick is that now you have started, keep it up - even if you only do it a couple of times a week with him, I am sure that you will get results eventually.