Transit Visa required for Swiss to India via London?

I am travelling next week from Zurich to India via London. I need to confirm whether or not I will need a transit visa. I am an Indian national and holding a Swiss Resident Permit of L Type which is valid till end of Feb 2021. Does this mean, transit visa is an exception for me? As per exemption list provided on below link, I should not need transit visa if I have a common format resident permit from EEA or Switzerland. I tried calling and raised queries with airlines and immigration office but getting mixed reactions. I believe their answer is based on who is answering it rather than what it should be.

If anyone of you have experienced this kind of travel, please help me out

https://www.gov.uk/check-uk-visa/y/i...ewhere_else/no

Are you travelling on a single airline, with a direct connection (of less than 12 hours), connecting between two different airlines airside, with no need to ‘enter’ the UK? Or on two separate tickets requiring you to go landside?

The website makes it pretty clear. If you’re not leaving the airport in London and you have a Swiss residence permit then you don’t need a transit visa.

Leaving the airport means not staying airside. ie passing through UK customs.

I hope that's a typo.

Exactly. You need to be on a transit ticket with your luggage checked through. But ZRH-LHR-India sounds like that would be the case.

If it’s BA. But it could be on two tickets LX-LHR-AI which would require entering the UK.

Yes. My airline won’t change and also the terminal. My waiting time is approximately 2 hrs on terminal 5

Sorry it’s end of Feb 2022

I think so cause my airline and terminal is not changing. I will collect my luggage finally in Mumbai

I am having a single ticket reference for my onward journey which means a single ticket right?

Right. You don’t need a transit visa.

Thanks a lot 👍