The FAQ on the Fiance visa tries to lay out the guidelines plainly (http://www.easyexpat.com/en/faq/departure/q81.htm)
"People who are planning to marry a British citizen or permanent resident in the UK may apply for a fiance/fiancee visa.

Fiance/Fiancee Visa Requirements:
# The sponsor and the applicant must intend to get married within a six month period.
# They must have met each other.
# They must intend to live together permanently.
# The applicant must be able to support him / herself, or be supported by their partner, without access to public funds.
# There must be adequate accommodation in place.
# There is no requirement that the applicant and the sponsor have lived together before applying.

Successful applicants receive a 6 month visa in which to come to the UK and get married. They are not allowed to work while on this visa. Once married, the recipients must apply for a marriage visa."

So yes- you may not work on this visa. If you are married and qualify for the marriage visa, it appears you are eligible for work. http://www.easyexpat.com/en/faq/departure/q82.htm

"This visa is for people who are married or in a civil partnership with a UK citizen or permanent resident. UK citizens and permanent residents are able to sponsor their spouses or partners for a marriage visa. Dependent children can also be included on Marriage Visa applications.

Marriage Visa Requirements
# The sponsor and the applicant must be legally married or in a civil partnership
# They must have met each other
# They must intend to live together
# The applicant must be able to support him / herself, or be supported by their partner, without access to public funds
# There must be adequate accommodation in place

Once the visa is obtained, (if the marriage is less than 4 years old) there will be given a 2 year visa to live and work in the UK or or (if Applicants who have been married and lived together for 4 years or more) they may be granted Indefinite Leave to Remain."

Is it possible to marry before your move? Hopefully this helps to clarify

 

Hi there,

I am getting married in 2 weeks to my English muffin.. I have posted back and forth concerning the settlement visa process. You need to make sure you read the details for the visa entirely. The link above are a great way to start. Here is a link on the thread where i posted a lot of useful information. good luck! It's a lot easier to do this in the states than in England, but you can't do much on expediting. It can take up to 120 days for the visa to process, but apparently most people get it within the first month or so. I put up a time chart on this thread below. Good luck!

how-long-processing-time-for-marriage-visa-t25706.html