Pam all this stuff has changed so much in the last twenty years that it's a little confusing at times. What I was issued was a Settlement Visa, last time I did this it was'nt for Spousal Settlement so it's all kinda new to me. This is what I got from the Home Office website:
2.5. Granting leave to enter
.
All passengers who have an entry clearance endorsed "Husband" or "Wife/WYR" should be granted leave to enter for 2 years on Code 1 and advised that, provided the marriage is still subsisting, they should apply to the Immigration and Nationality Directorate for indefinite leave to remain not earlier than one month before their leave is due to expire.
Only spouses who have completed a period of 4 years as the husband/wife of a person who has a right of abode in the United Kingdom or indefinite leave to enter or remain in the United Kingdom and who is on the same occasion seeking admission to the United Kingdom for the purposes of settlement, having lived together abroad with their spouse throughout that 4 year period should be issued with an entry clearance endorsed "settlement". These endorsements are rare.
Spouses in possession of an entry clearance endorsed "settlement" should be granted indefinite leave to enter
So from what I can gather is if you've been married to a U.K citizen for 4 or more years and living in the States and then both decide to return to the U.K for settlement then you bypass all the FLR/ILR procedures and enter on a Settlement Visa with automatic ILR with no restrictions, although they claim that this is rare, but that seems to be exactly what I got. Some are issued with various restrictions such as "No Recourse to Public Funds", etc.
Maybe they take into account your financial situation and other variables taken off the 16 page application...to be honest, I do'nt know. I do know that years ago you needed to implement any visa you got within 90 days from the date of issuance but this one says "Indefinite Leave to enter the U.K" and is good until 2014. Like I said, this is the first Spousal Settlement Visa I've ever been issued. I've had two others, one issued by the miltary which allowed me to go back and forth and another was a family sponsorship visa because my oldest natural daughter is a U.K citizen but that was over twenty years ago and they've changed probably a hundred times since then, so in a way, this is all new to me.