Great info, thanks for sharing.

Apple say that the mid-2012 MBP only supports 8Gb RAM - is that correct?

No it supports 16GB.

http://www.datamemorysystems.com/app...mory-upgrades/

In US $85 vs $158. I would go with 16. Or at least use 8s one a time, you would 10 with existing 2 an 8, though matched pairs of of same are best.

Is it possible to tell from the serial number which model a given MBP is?

I have been offered one at a steal of a price, but the guy is away. He says he bought it in Feb 2012. Is that the same model as in the OP? I do have the serial number here.

The date is enough to age it. That would be a 2011 model, as the newer ones were released in mid-2012. The 2011 has USB 2, whereas the 2012 ones have USB 3.

There are a number of websites where you can enter a serial number and get info about the hardware, not least of all Apple's own:
https://selfsolve.apple.com/

Could try https://selfsolve.apple.com/agreementWarrantyDynamic.do
Or get the model identifier and check with mactracker

Do not forget about Apple's Refurbished site on its site and also its sister site on ebay. Even new Mid "2012 new" aka 2013 New Classic Non Retina 13s are a pretty good deal if its feature set meets your needs. I would avoid the 2011 Model because USB 3 is much better for external storage. Of the top of my head do not remember other differences but likely the Integrated Video was improved again and a small refresh of the CPU.

Older than the model in the OP then. OK, shan't bother.

That said, I'll keep an eye open for that mid-2012 model, as it sounds like it will be an ideal mid-level machine for some years to come.

I would try and find the 2012 Mac Book Pro Unibody ( the last ones ).
We have been buying them up lately as they are amazing machines.
We get them in the range of £900-£1300 in my money depending on build.

Was that late 2011 MBP a Retina then? My MBA 2011 is sold at a great price and I have been offered the 2011 for equiv: £375. Good buy?

None of the Unibody MBP are Retina. There are Build to order options for Matt/HI res screens but these again are not Retina models.

Mactracker is a great source for all models.

As we have said the 2012 MBP the the best of the Unibody MBP and £375 is a good buy.

I'll take it then. I can get 16GB of RAM for equiv: £120, so it can sit on my porch for morning work. ;-)

Do you remember what kind of battery life the 2011 had?

Before you buy ask them for model identifier of machine.
Yes 16gb is happy days as would an SSD
I would expect 3-4 hrs on light use and 2 hrs heavy use on battery of that age.
You may need a new one at some point

I have the RMA SSD sitting here, as yet not installed in the Mini. Is there a better SSD I can get for my 2011 mini these days?

I tend to buy Crucial or Samsung Pro/EVO drives.

Two things:
Firstly, the 2011 model doesn't have USB 3. Apart from that, it's still a great machine, with FireWire, Thunderbolt and Ethernet and DVD, etc, etc.

Secondly: the battery on those is fairly easy to replace, if you have the right screwdriver. It uses a Y-shaped screwhead, but there's only a couple of screws and then you just take it out. I got a genuine new Apple part from eBay for £30.
I'm getting 6 hours on average usage. It's the same battery model.

Picked the machine up last night. It's a bit of a lump, but it won't be travelling much, so no bother really. Really enjoying the screen size and it's in pristine condition.

It's still on Lion, so MavX d/l now. Über slowly. The previous owner fitted a 750GB drive, so only some more RAM needed now.

@benwiggy:
I don't have that driver in my toolkit. Does it come with a new battery, or is it a separate purchase?

You can get the screw drivers on Amazon end elsewhere for around $7. There called Tri Wing. They are also often described as being for a Nintendo.

Are there any high-quality aftermarket batts for extended life?

I believe the short answer is No. If anyone had good ones would be Macsales, they do not seek for machines newer then 2009, non unibody.

Amazon has many.

The only real question is one of risk of the battery doing harm. I think I would stick to OEM. There are pretty good review on there though.