Like @Bluntness100 I also wonder if the marriage is legal and binding, and if the OP is even married at all. Also like @HeronLanyon I am struggling to get my head round the 'fact' that someone can change their name now and have it retrospective and change everything from the past.
Also, how and why did the registrar put the 'wrong' name on her marriage certificate? They don't make mistakes like that. They would have copied the name from her birth certificate. So it seems bizarre that this error occured.
@Christmaspug
As many posters have said, all you need to do, is to scrap this application (sorry you will lose the £80,) and then speak to the registrar, because if they did put your forename down wrong on your marriage certificate, then they need to rectify it, and re-issue the marriage certificate. Also, check your marriage is legal!
I am genuinely baffled as to why and how this happened though. Also, surely you must have looked at your marriage certificate, and seen it wasn't your proper given/birth name? How have you gone along with opening bank accounts/getting loans/mortgages?
Also have you never had anything official given to you, like a degree certificate? I can't believe, in 30 years, (since you became an adult,) that you have not had a single occasion where you have needed to use your official name - the one on your birth certificate.
But yeah, speak to the Registry Office. I would. Also, PLEASE tell me you haven't booked, and paid for your holiday before getting your passport!!!