Help my son get a diagnosis

First i would like to thank you for reading our page, we are looking for help with finding a diagnosis for our 3yr old son. From the age of 4 mths old he was diagnosed with external hydrocephalus (fluid on the brain), we was told it would cause no problems other than a large head, it became clear that our son wasn't developing as our other children had. He was late to crawl, walk and even learning to talk was a problem . He regularly saw a pediatrician who never seemed concerned so I fought every step of the way to get him all the help I could, he is developmentally delayed but doing well. He has hypotonia as well as muscle weakness and some hypermobility. Last year after continuesly saying something was wrong with his eating he had a videofluoroscopy which showed he has extensive oral motor disorder which means he chokes gags and has on occasions choked badly where I had to intervene, he also during eating has aspiration which means food and liquid goes down his airways to his lungs. He has tape therapy for this. In the beginning of July 2015 he woke up and was limping which over the morning seemed worse so after a trip back to our local childrens ward we was told it was probably a virus, he wasn't in any pain but was clearly struggling to walk, we took him back 2 weeks later where a different doctor didn't know what was wrong and sent us for Physio, the orthopaedic physio said she thought it was neurological and sent her report to his consultant. Alfie's consultant ordered blood test but said they were OK she also done a genetic test which I still haven't got the results for despite asking lots of times. We was referred to a neurologist in London. We was still waiting for a appointment with a different neurologist who was off on long term sick regarding his development as a degree of cerebral atrophy was discussed in his previous MRI scans. We finally went to see a different neurologist who found a few things and had also referred us to opthmology as his pupils didn't react the same which they have said his optic nerve at the back Of the eye is very small so they are watching for further determination. She said they were looking for a possible neurodegenerative condition, and ordered more blood test which we still don't know what they were. In may this year we went back up to London for a follow up, this time we saw a different neurologist who bent Alfie's fingers and moved his joints then said oh I think he has joint hypermobility and that's his problem. Our son in the last year alone regarding his right leg has seen a total of 9 professionals all contradicting the other and not one can give a diagnosis. Our son can't walk for more than 5-10 mins before he starts limping and dragging his right leg he cries his leg hurts he starts falling more then his leg gives way and he can't go on. We are having to constantly have a buggy even for simple things like the park or family days out, he wakes in the night crying saying his leg hurts. He doesn't run like other children his age he is slower and clumsily staggers. Not one person has done a MRI of his brain or a xray of his pelvis and legs all that has been done is bloods. I can't stand seeing my son like this and I just want to get him the help he so desperately needs, I was told by his consultant that she can only do so much via the NHS and basically they don't know what's wrong and only time will tell if he gets anymore symptoms or if he completely stops walking. I'm literally and my wits end I don't know who to turn to for help. I just know that something has happened to my son and no one knows what's wrong but aren't willing to scan him etc due to budget. So I'm asking for your help to raise money so I can take him to a private specialist in London and pay for medical investigations, I don't know the full amount needed as a consultation alone cost £300 before any testing and results, a mri is looking to be over £1000 as he needs sedation then there is other testing they are likely to do. I wouldn't ask but I really don't know what do anymore I have fought so much for the help and therapy he has now for the other problems, my husband is currently working away 6 days a week so only gets to see myself and our children for 1 day just so that we can try and save to pay for medical treatment but it's going to take months on end to get just a small amount. So please help our beautiful boy. Thank you for reading. God bless you.