New 12v Battery and some other bits?

Yes and yes.
Your battery is definitely worn out. It's amazing that it starts up at all.

But wait with the wheel sensor until after the new battery is in place for a couple of days.
I would suggest checking the connector at the wheel sensor first too.

 

oem is fine, but so are aftermarket. i believe @Britprius recommends exide

are all four tires the same brand and model?

 

euro car parts?

 

Have you checked with the dealership, what they have, and price?

 

Who is "they" ?
And Lithium Ion is not the same as AGM.

 

Good catch. Silly me thought that "lion" must be some English battery brand, since he's from the UK.

I agree on the general points above. The 12V battery is toast (well, unless there is a problem with clamps, cables, etc.). And it would not be a surprise if replacing that makes other problems go away, so replace that first before worrying too much about other issues. Then worry about the other issues.

 

Strange that site doesnt have reviews?
Is that common in UK?

bf19 gives 50% off tho

 

Lion is a brand name.

If there's a Toyota dealer nearby, I'd check there first. Really good batteries. But most any auto parts store should have something for the Prius.

 

Well I guess it IS a brand of battery.
Sometimes things ARE what they appear.

Any AGM battery of the right physical size and with the right posts should be fine.
Don't think we have too many owners here in the UK.

 

Try dropping in? They can't all hide under the counters, lol. You're probably right, it'll be a fool's mission, but who knows.

 

What's your use of the car like? is it driven daily, or at least several times weekly, and how many miles, what kind of trips?

Do you sometimes sit in the car in "accessory" mode, listening to the radio for protracted time?

Any "incidents", door left ajar overnight, stuff like that?