Hi and welcome to the forum.
My avian vet is about the same distance away as you are to yours. I have in the past travelled further to get a bird to a specialist. I have travelled both aviary and hand tame birds. Some like to look at their surroundings as they travel and some do not so I always take a towel and place it so the bird can see me and only me whilst driving if necessary.
My african grey Denarii was under anaesthetic on Friday the gas they use for birds is isoflurane gas if your bird is to have a procedure than the bird needs to fast for 4 hours in a parrot and think its about 8 in a raptor it's so their crop is empty and they won't be sick as they come around.
All vets charge different rates and they should tell you what the charges are before the undertake any procedures. On Friday I paid just shy of £300 but this was for two x-rays, gas, 4 medications, blood sample and diagnostics, a nail dremmel (trimming of all of her claws) and removal of a broken feather shaft in the tail that the vet came across whilst he was doing all the other stuff. All in all very reasonable price I thought for all that was done, avian vet earned his money 100% ... especially as it was me as an owner poor chap had to deal with lol. None of my flock are insured, it works out cheaper for me with my lot not to be and to save the money in a parrot slush fund for them to use when they need it
Your stuck between a rock and a hard place I am afraid..... if you don't go this what-ever-it-is could go unaddressed and cause permanent damage affecting the birds life quality forever and you punishing yourself about it forever. If you do go then ok its a hit to the pocket but and a nervous time but with the possibility of high status of getting it sorted out now once and for all and ensuring your bird has the best quality of life ahead of him/her and you being totally aware of what is or is not to come. Ok that sounds scary BUT could be a cure and a never to be seen again thing with a vet visit and treatment. Weighing it up for me it would be a done deal .... avian vet every time. Loosing one bird that made a huge alteration to my life which was DizzyBlue just about finished me off had I been able to get to an avian vet in time I would have sold my soul to the devil to have had more years with that bird. Being fine before and after .... that is in your eyes no offence but we all know that birds hide their illness as in the wild they would be eaten for any weakness shown so could be an illusion the bird has spammed out to you so you think everything is totally normal.
A good examination, bloods taken to see if there is anything going on and then peace of mind you are doing everything for your beloved feathered friend .... can't really put a price on that
Whatever you decide to do make an informed decision one way or the other, asking the forum the question has given you years of experience in their replies in loving and living with our feathered ones from the above members who wouldn't ever be without their feathered family members I don't see any of us saying see how it goes and then decide. It's a lot to take in and hard when you think ooo but its risky ... its even harder if you do nothing. We make the decisions and our feathered sweeties are the ones that have to live with those.
I don't wish to sound negative or hard or any such thing I wouldn't judge another person for them doing things differently, but you asked the question and the above is the answer of what I would do. I hope you stay on forum and let us know how your little one gets on one way or the other. And if you want to know anything just ask away, that's why we hang around here to help each other through good and bad times and share our parroty fascination.