Oscarsmum - I'm new to running as well, just over 3 months so far, and it was parkrun that got me started. As I've learned a bit more about running, I've been told, am beginning to understand and also see the benefits of the long run, and I'm reluctant to give up one in favour of the other so most weeks I'm doing both. I'm also up to about 8 miles with my long run by the way.
Some would probably say that having 2 'hard' days back-to-back is too much, particularly in the early days, but I'm 42 years old and so far so good in terms of avoiding injury and the rapid improvements I'm seeing in my running.
Is there any other reason why you couldn't do both yourself?