Exemption from English Language Test because of long-term sickness

[Bambino-fred]

I was wondering if the British embassy in Colombia has a list of approved doctors that it works with to provide medical reports.
I understand people may not have specific information about Colombia, but maybe you aware of various embassies doing this and if that is the case, I will try to find out more.
I am asking this because it is very difficult to find a doctor who is willing to provide such a report and then fully cooperate with the authorities to verify the report.
I would be grateful for any tips / information about how to go about doing this.
And just in case you will ask, yes my long term girlfriend has several long-term health conditions that make it very difficult for her to perform well in a speaking / listening test.