Very helpful. Thank you.

Hello. I'm writing to seek advice from people here.
Several years ago, I was an international student at a uni in UK.
While I was doing an MPhil there, I was also a PhD student back home.
Then, when I left UK with MPhil, I had to start working and dropped off from the PhD.
Now I have a tenure position at a uni in my home country,
however, as I do not have a PhD in my field, I am teaching something different here.
Trying for PhD again has always been at the back of my mind.

So my questions are: if I apply for a PhD in UK by distant learning,
does my research plan have to be just different from that of my past MPhil?

Am I not supposed to use any parts of my MPhil thesis?
(If I apply, I will have to apply for a different uni from the one I graduated from,
since the school I studied at doesn't provide a distance learning PhD.)

As I am an international student, the tuition fee will be like 15000GBP a year.
That's not impossible, but will pose a very heavy burden on my life.
Does having an MPhil from another institution help shorten my PhD period?

Or, tell me anything you think of PhD by distance learning.
Thank you.