Hi guys I worked for autoglass for years and your right both front and rear screens are both bonded to the car. Both are easy to get out with the right tools! same as any job.
The bodyshop should remove the window to do the job right or pointless doing the job as will come back in a matter of months!!.
The old trim will not come out at all if fitted right and will need to be cut to remove window. looking at screen your see a thick ridge and a flappy bit cut the flappy bit off so you have a gap ie bodywork a gap about 5mm all round trim. now remove panel from inside remove heated screen wires etc and rear wiper arm if needed.
squirt soapy water around gap find the biggest gap and twist the blade from this http://www.ebay.co.uk/itm/SILVERLINE-NEW-WINDSCREEN-REMOVAL-REMOVER-TOOL-/350137664126?pt=UK_Hand_Tools_Equipment&hash=item5185d4c27e in glue **UNDER** the window not in the old trim hold handle with blade away from you alittle and pull the t-handle to you like this
(just don't be like this twat!! or you will scratch paint or worse brake the screen like he did bottom of p/s)
when screen out cut all old glue off then repair the panel cos if don't you could repair panel then paint it then find the old glues still there (1) window WONT fit back in (2) your Fresh paint could get damaged cutting old glue back,
Refitting is just as fun lol!! find something like a bin or workmate etc covered by blanket to lay glass on so don't scratch glass with a new blade trim old glue back flat as pos but watch for heated screen terminals, window tint etc fit new trim make sure its the right way around!! and join mark is in centre of BOTTOM of screen should be little maker in the paint on the screen then clean screen with glass cleaner and then wipe the black paint on screen and body this brake cleaner so remove any dirt grease etc
use this for refitting http://www.ebay.co.uk/itm/WINDSCREEN-BOND-GLUE-SCREENFIX-BEST-PRICE-ON-eBay-/220707762447?pt=UK_Body_Shop_Supplies_Paint&hash=item336335310f
prime the glass with one good line all around screen and trim and same on body MAKE SURE DO NOT GET ON PAINTWORK!!! one line over where old glue line was
let them both dry about 5 mins
then stick something like this http://www.ebay.co.uk/itm/Small-Dent-Puller-Lifter-Glass-Car-Suction-Sucker-Clamp-Cup-Little-Mini-Pad-Cup-/400468023086?pt=UK_Hand_Tools_Equipment&hash=item5d3dc1172e on outside of screen in middle
I WOULD DRY FIT THE GLASS FIRST MAKING SURE TRIM ON RIGHT WAY AROUND AND HAPPY WITH THE FIT!!
using mastic gun start in middle of bottom of the window glue and the way around trying to just touch edge of trim (glue hight about 10-12 mm) smooth join into one then slowly lower screen back in and gently firm down all around and then refit everything back ie trim wiper etc
any probs pm me your phone number and tell you better
or if a good bodyshop there do all this for you! but your pay for it
hope this helps guys
ps rear window trim part number is T75573-14210 and about £55