Elusive Swallowtails at Strumpshaw Fen

At 11.45am I arrived at a very busy Strumpshaw Fen and was advised by one of the Wardens there was no spare parking and to visit Buckingham instead, not a lot of good when you had gone specifically to photograph Swallowtail butterflies! I found a place to park just up the road and was fortunate to bump into Roy & Ruth H. It was really good to see them and we walked up the Lackford Run seeing first Large Red Damselfly, some green beetles and a Swallowtail with closed wings that looked settled on a reed, a couple were taking pictures of it but it flew just as I got the camera out! Typical. It flew over the path and out of sight. I have never seen so many people here before it was as busy as Piccadilly Circus. Both Sedge Warbler and a male Reed Bunting up a reed stem and a Cetti's Warbler briefly seen after it sang its explosive call. By reception, a Singed Moth seen on the back of a post. I decided to go back to the Dr's garden still no Swallowtail but both a fine and very pale 2 Painted Ladies seen plus a Holly Blue. During the first part of the Lankford Run, I saw a fine Swallowtail feeding (with it flapping its wings very fast on the vegetation on the right of the path but as soon as I took a step closer (I was still 5 metres from it) it flew over the path and over the reeds and out of sight. I decided to go back to the Dr's garden still no sign but I then decided to try the Meadow next door & back with Roy & Ruth immediately Ruth said they've got one, another fine Swallowtail was flying about and initially settled but there were around 5 people scrambling after it (including a well known Norfolk photographer) and I saw it fly right round the corner and over the field. However, a Norfolk Hawker was found perched on a bush and we all took pics, it was very obliging until someone else came in and stepped and pulled a blade of grass and her shadow passed over it and it then flew off. I went back to the Dr's garden & still no sign of Swallowtails there. Back at the meadow just 2 people remained and it was around 4pm that I got shots of first up to 3 obliging Brimstones occasionally settling on flowers, then on 3 occasions a Swallowtail appeared (within a few minutes of each other) and fed low down on flowers, my fellow photographers all posed good fieldcraft and we managed to obtain shots but disaster for me as the camera had switched the focusing square from the middle to the left hand of the screen which meant on some pics the left wing was partly cut off, I only discovered this after I had taken the pics. So will be back there again next weekend if the weather is OK. A Hairy Hawker flew around settled and posed well for the trio of photographers.