I will be traveling to the EU Schengen Area this summer from the United States this summer with my SO. I am U.S. Citizen, however she is a PRC passport holder and a U.S. permanent resident.

Currently, we have round-trip flights booked US-MAN. Our plan right now is to arrive into Manchester, spend the night in London, and fly out of London to a Schengen destination (e.g. Berlin) the following day, and the reverse on the route back. According to Gov.UK, I was given the following when checking for Visa requirements for transit:

"Transiting without a visa
You might be eligible for ‘transit without visa’ if:

* you arrive and depart by air
* have a confirmed onward flight that leaves on the day you arrive or before midnight on the day after you arrive
* have the right documents for your destination (eg a visa for that country)
One of the following must also apply:

* you’re travelling to (or on part of a reasonable journey to) Australia, Canada, New Zealand or the USA and have a valid visa for that country
* you’re travelling from (or on part of a reasonable journey from) Australia, Canada, New Zealand or the USA and have a valid visa for that country
* you’re travelling from (or on part of a reasonable journey from) Australia, Canada, New Zealand or the USA and it’s less than 6 months since you last entered that country with a valid entry visa
* you have a residence permit issued by Australia or New Zealand
* you have a common format residence permit issued by an European Economic Area (EEA) country or Switzerland
* you have a residence permit issued by Canada issued after 28 June 2002
* you have a uniform format category D visa for entry to a country in the EEA or Switzerland
* you have an Irish biometric visa (marked ‘BC’ or ‘BC BIVS’ in the ‘Remarks’ section) and an onward flight ticket to the Republic of Ireland
* you’re travelling from the Republic of Ireland and it’s less than 3 months since * you were last given permission, on the basis of holding a valid Irish biometric visa, to land or be in Ireland
* you have a valid USA permanent residence card issued by the USA on or after 21 April 1998
* you have a valid USA I-551 Temporary Immigrant visa issued by the USA (a wet-ink stamp version will not be accepted)
* you have an expired USA I-551 Permanent Residence card issued by the USA on or after 21 April 1998, with a valid I-797 letter authorising extension
* you have a valid standalone US Immigration Form 155A/155B issued by the USA (attached to a sealed brown envelope)
You won’t be able to transit without a visa if a Border Force officer decides you don’t qualify under the immigration rules. You can apply for a transit visa before you travel if you’re unsure whether you qualify for transiting without a visa."

What I am uncertain about is whether "transit" is acceptable between different cities, such as US-MAN/LHR-EU? I have tried e-mailing through the contact form on Gov.UK several times now and keep getting the same non-informative copy/paste reply. I would rather not pay to call the UKVI pay phone line (which is ridiculous IMO), so I was hoping that someone here at FT might know more or had experience with this in the past?

Thanks!