'To have loads of notice': meaning in context

Dear all:

I am currently reading a book by Alan Kay entitled This is Going to Hurt, in which the doctor-turned-standup performer narrates his misadventures at the time when he worked as a house officer in a hospital in Britain. The book was written as a series of entries from his 'secret diary'. Here's one such entry, with the background two passages italicised:

Saturday, 23 July 2005
This weekend is my best mate Ron’s stag do, and I’ve
had to bail out with barely four hours’ notice. It’s
annoying for a million reasons, from the fact it was just
a close selection of pals with only eight of us making
the cut, to the personalized T-shirts, to the now-uneven
paintballing teams, to the fact I spent four hundred
*** pounds on it.

I was originally due to be working, but arranged a
four-way swap (A doing my shift, B doing A’s shift, C
doing B’s shift and me doing C’s shift) – so it was always
slightly precarious, like a house purchase in a massive
chain. And now C (who I’ve barely met before) has
real or imaginary childcare issues for one of her real or
imaginary children, so I’m here on the ward instead of
Zorbing, off my tits on tequila.

Non-medics struggle to understand it doesn’t actu-
ally help having loads of notice for this kind of thing:
more than two months’ notice means we don’t have the
rota yet. I order a bottle of whisky I can’t afford – I can
virtually hear Elton John saying ‘Steady on, let’s not go
crazy here’ – and arrange to have it delivered to Ron’s
flat on his return, alongside my grovelling apologies.
We arrange a stag-do postscript for just the two of us in
a fortnight’s time – after my run of nights, and after the
three locum shifts I booked in to cover the cost of the
weekend I’m now missing.

The question is: even though I can understand quite well what 'notice' is (some pertinent information given in advance), it escapes me how this meaning can be applied to the underlined instance and how it could be paraphrased.

In short: what is the meaning of 'to have loads of notice' here?

Your input would be greatly appreciated.

Best wishes,
Jacques