Hi zc
I think it would be helpful for you to have a chat to an obstetric anaesthetist at your local hospital before your planned CS.Most places have clinics where women with medical problems can be seen well beforehand in order that the anaesthetic can be planned. They would also see people with specific requests like yours or women with needle phobia for example.
There are small but increased risks to a GA in late pregnancy. This is largely down to the physiological and anatomical changes which take place. For example, pregnant women are always treated as having a " full stomach" when undergoing anaesthetic - this is because the baby squashes your stomach and makes you more prone to reflux ( as you obviously know!).Precautions , such as antacids and a specific way of getting you off to sleep, are undertaken to avoid this.
In late pregnancy your body consumes more oxygen ( because of the baby's requirements). This means that your blood oxygen level drops much more quickly if there is a problem under anaesthetic than it would if you weren't pregnant.
Pregnant women are more likely to difficult to intubate ( or pass a breathing tube into the wind pipe). This is due to anatomical differences ( such as oedema and big boobs!). Historically, this led to problems in the 1970s and 1980s when most CS were done under GA. Failure to intubate and oxygenate the mother led to maternal deaths . This was the main reason that most CS started to be done under spinal or epidural in the 1990s.
So far so scary. Most GAs are now done for emergencies when there is no time for a spinal or when a spinal is clearly contra-indicated ( clotting problems, back surgery etc). However, the absolute risk of a planned GA CS is still very small. Your chances of a failed intubation for example are 1 in 300 . There are now clearly defined "drills" of what to do if this happens and so your chances of coming to serious harm even if this does occur are even smaller.
I would think the main drawback to you would be, as others have mentioned, missing the birth yourself and your partner not being present. You might also feel groggy and a bit out of it for a while.
The bottom line is that no anaesthetist can force a patient to have a spinal if they don't want one. Most would give you a GA if you asked for one & definitely if you absolutely insisited( although they would explore your reasons first and explain the risk/benefit as above) Patient refusal to spinal is an absolute contra-indication to doing one. It sounds like the problem wasn't the spinal itself last time but the rather rude manner of those involved for which there is no excuse.
I'd suggest asking your midwife if she could arrange for you to see an anaesthetist well before your CS. They will have your old anaesthetic charts and should be able to see what happened. Be frank if you do see them. If the problem was a rude anaesthetist then tell them so . It's likely that they'll be aware of who their grumpy colleagues are.
HTH.