Foreign Wedding Couples requirements
The legal requirements for someone from a foreign country to enter the UK for the purpose of entering into a marriage or civil partnership can be found at 'UK Visas and Immigration' on the UK government site https://www.gov.uk/check-uk-visa.
If you click on the country you are from and use the heading Visit, this will bring up the Visa price for "Visit for marriage and civil partnership" amongst others. This will go through the process for your nationality. It can take some time as it may involve Biometric information and registration prior to submission. Parties to a marriage who are not British, Swiss or EEA must complete a Home Office Declaration of Immigration Status form which should accompany the marriage form. Registrars will not accept notice without the completed Declaration Form. The Declaration form can be downloaded from www.nrscotland.gov.uk and is also on my forms list.
I strongly suggest that you contact the local Registrar for the area in which you are to be married as soon as possible as they are all very helpful and will confirm those procedures you will need to complete in ample time for the wedding to go ahead.