stop over in UK fro 3 days PR card holder

[themann_ca]

HI,

trying to find out if my wife needs a UK visa or transit visa for UK

She is a PR card holder and has a Indian passport.
we are traveling from Canada to India (round trip). But i booked a 3 day stop over in UK on the way going India.
by what I've understand so far is because the stop over in more then 48Hrs she will need to apply for a visitor visa before leaving Canada (we don't have enough tie for that)??? or is it possible to apply on arrival?

or I can reduce the stay by a day (change flights $$). and leave UK within the 48Hrs. so I wont have to apply for visa here in Canada? and apply for a transit visa when landing?

I was reading online on the UK Gov website:
https://www.gov.uk/check-uk-visa/y/india/transit/somewhere_else/yes

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)
• you have a residence permit issued by Canada issued after 28 June 2002

Our Flight currently arrives in UK Sat morning , and departs Monday evening.
if I want the above conditions to be true, I would need to arrive Sunday Morning stay one night in London and leave Monday evening


thanks ,
looking for advice