Grumble away! I'm not an expert, please don't think I am - just spent years trying to figure out what was wrong with myself - and the specialist patient training has been helpful. Good to hear you're revisting GP, hope it's a helpful consultation.
If it was cervicogenic then the root of the problem physically lies in the neck and the headache is 'referred' pain - like when someone has heart truble but feels pain in their left arm. The cause of the original problem could be stress, (not unlikely in you case with all that's going on), illness (eg arthritis) or injury (eg whiplash). I have a friend who has these sorts of headaches (and it does sound similar to what you describe) and she has found a number of things helpful. She finds massage very helpful (DP any good?) - particularly deep, kneading type massage, the light stuff might make you feel worse. Trouble with massage though is your muscles get so used to being 'wrong' they don't like being made right again - for this reason I'd combine massgae with going to see and osteopath - a good one will do both for you. This can be expensive though and you'd need to commit to a few sessions to get lasting benefit. The NHS version is physio but I think they're not specialist enough personally (unless they've had extra training or have a special interest in headache). My friend also has chinese acupuncture (western practitioners though), as do I, and we both have found it helpful. If you like I can see if I can get my practitioner to recommend someone in your area.
Just realised I'm esay writing again - sorry! nearly there...
This is definitely a personal thing but one thing I swear by is Tai Chi, if you can't do that Yoga - and DD could go with you to those. They both involve lots of work on balance, posture, relaxation and stretching and are just really healthy things to do generally. If you decide to try them though tell the teacher about your suspected neurological problems though just in case they'd want you to avoid certain things. My DH does yoga (when he can be bothered) and I do Tai Chi (when not pg!), neither of us would swap so I think it's just finding what suits you.
Pg is going well, thanks for asking - maternity leave starts on wednesday (thank God!) and I'll be 38 wks on thursday. Breastfeeding network has sorted me out with medication to take when baby arrives too so fingers crossed all will go well in that dept. Looking and feeling like a whale - definitely ready to pop!