I was recently in the London for about a month and a half after traveling around the EU for two months prior. I ended up suffering a bad injury that forced me to come back to the US so my family could help me recover and so I could convalesce accordingly. I bought a roundtrip ticket, allowing myself to stay in the states for 7 weeks, and plan to go back hopefully by the end of August. My question is, since I left for about two months, when I return will I have an additional 6 months in the UK or will I only have the four months? A follow up question would be, how long do I have to leave before I can come back for another 6 months? Thanks so much!!
My question is, since I left for about two months, when I return will I have an additional 6 months in the UK or will I only have the four months?
If you have a successful landing interview you will get a brand new 6 months 'leave-to-enter' stamp in your passport just like it happened the first time. The controlling reference is Paragraph 23A of the rules...
23A. A person who is not a visa national and who is seeking leave to enter on arrival in the United Kingdom for a period not exceeding 6 months for a purpose for which prior entry clearance is not required under these Rules may be granted such leave, for a period not exceeding 6 months. This paragraph does not apply where the person is a British National (Overseas), a British overseas territories citizen, a British Overseas citizen, a British protected person, or a person who under the British Nationality Act 1981 is a British subject.
With regard to your question about the four months, it's history. All unspent leave is forfeit when you leave the UK. This is laid down in Paragraph 20A of the rules.
20A. Leave to enter or remain in the United Kingdom will usually lapse on the holder going to a country or territory outside the common travel area. However, under article 13 of the Immigration (Leave to Enter and Remain) Order 2000 such leave will not lapse where it was given for a period exceeding six months or where it was conferred by means of an entry clearance (other than a visit visa).
A follow up question would be, how long do I have to leave before I can come back for another 6 months?
There are no cooling-off periods where visitors are concerned, all you have to do is successfully complete a landing interview each time you show up. Your question suggests that you might be seeking to base yourself in the UK and hence not a genuine visitor. If the Immigration Officer makes this conclusion during your landing interview you will be detained and bounced. It's a devastating experience and will mean the end of visiting the UK for quite a while, so be well prepared. The landing interview gets more invasive on each successive visit.
In fact you can expect the difficulties to start when you show up on August, but it won't turn in to detention and a lengthy grilling until your 3rd or 4th visit.