If you are in the UK look up Europarts.

Why would you replace them with Asian shocks?  The originals are
Sachs/Boge brand and are available outside the dealership at reduced
prices.  Most people who want to upgrade their shocks will buy Bilstein
or Koni.  I have no experience with Konis, but have nothing but good
luck with the Bilsteins (german manuf.)  If you are only replacing the
rears you'll want to use their "touring" series which are about the same
dampening as the stock ones.  The Heavy duty series has considerably
more dampening, but they should be installed all around, not just on one
axle.  The Sport series are made shorter for use with stiffer lower
height springs, so you'd have to replace them all around and also
replace the springs at the same time.

-Fred W

If the tire store sells shocks, I'd suggest a second opinion before you do
anything.

You could need shocks by now, but the odds are better that you do not, and
the tire store is motivated to sell you extra stuff if they do that kind of
service.

EXAMPLE
I bought a used minivan going on 10 years ago. It was a lease return that I
picked up from the dealership. I went to the Oil Change place that does a
wide range of vehicle services, and the service writer came back with a list
that effectively said that everything behind the hood ornament needed to be
replaced. His list of service items was in excess of $5000, and all I wanted
was an oil change and the tires rotated. I suspect a similar thing is
happening to you.

Get a second opinion. I can't imagine that you need shocks already ...

If you really do need shocks, follow Fred's suggestion, check out Bilsteins,
and get one for each corner.