Waiting times can be long (my gastro consultant's is 10 months) but it's worth checking. I waited ages for an appointment before I rang and asked as I was worried an appointment letter could have got lost in the post or something. Turns out they had "lost me on the system" somehow so just as well I checked. Test results diagnosing a condition had been received about 6 months beforehand which they had also missed so I could have been treated a lot earlier.
I had an MRI scan booked for last November. I had to postpone it as my nan died and it was her funeral. I waited and waited for another appointment and finally rang up to ask as I was worried my gastro appointment would come through without it. Turns out they had cancelled it by accident and it then had to go back through the consultant to re-order it and they hadn't booked in a consultant's appointment as they were waiting for the MRI scan. I finally had the MRI scan in July and now don't have a gastro appointment until December.
I had a rhumatology appointment last week and my consultant was asking why it took me so long to come back and see her as my joints were so bad, turns out I had an appointment booked, which I never received notice of, last March, they assumed I hadn't attended as I was feeling better so put it back another 7 months to October but my GP got them to bring it forward to last week. This could have been a post problem though.
I figure things can get missed especially with it being such a large hospital but it is frustrating. In my experience, ring and doublecheck things (I should have a lot more than I did) as you never know.