Can anyone clarify a position for me please regarding application for a spousal visa for my fiance, soon to be wife.

I have been told conflicting information regarding booking appointments with home office for same day spousal visa by immigration lawyers in London. One I have registered with have said that they are not able by law to book an appointment on our behalf for spousal visa application interview. Two others have said they have 'slots' booked and we can simply take one of those interview slots. As it is extremely difficult to get hold of anyone on the phone at the home office - we are stuck betweeen knowing what the best route to take and who to believe - they all will take our money of course!!

Thank you in grateful earnest for any advice or help.

Paul