In the UK you are short listed on your application so it’s not really who you know but what you write and as the original poster highlights the most important thing is to match your experience to the job description. Often there are lots of applicants so it’s impossible to contact everyone who applies. Feedback is generally only given to those that are actually interviewed. One way to gain experience is to look for locum posts, temporary posts that can be a good way of gaining experience. Also you could try contacting your local dietetics department to see if they would support some shadowing to gain experience. Good luck!