HELP! Cats are driving me crazy!!!

Hi Everyone.

I have two cats in a privately rented house close to two major roads
and more beyond those.

They have been used to coming and going through a cat flap. I had them
vaccinated, I.D. Chipped and Spayed when I was at my last place. We had
lots of fields and woods and endless safe exploring and
Getting-Up-To-Who-Knows-What territory.

Here there are two main roads that form a cross roads. There is also a
rising trend where I now live for lads with Pit Bulls and Bull Mastiffs
and other aggressive dog breeds to set their dogs on cats or catch cats
and throw them to their dogs to rip the cat apart for their
entertainment, sick! probably sadistic serial killers in waiting!

It's been quite warm and sticky lately with temperatures in the
mid-90.F range. I open the front and back bedroom windows to allow the
air to circulate, I don't like a bedroom to hot or too cold.

The problem is, that the back room window opened out from bottom to top
and from the window ledge it's a short hop on to the flat roof of the
extension. All the houses here have them in one form or another. I wont
allow the cats in the bedrooms. They have regular flea, tick and worm
prevention treatments but they both have the most infuriating problem
of selective and inappropriate soiling - they find something they like
the smell of, a pillow slip, a quilt, door mat, clothing left by the
washing machine and one of them will pee on it. Sometimes it's like
marking - just a spot but other times it can be a bladder full.
Thankfully they are both female so no male cat urine/spray odour -
unpleasant all the same. I have a spray bottle of something called
"Simple Solution" it smells strongly of Almonds (Which I love but cats
hate!) and has the appropriate enzymes to break down the components of
cat urine, removes the smell and the stain - IT REALLY DOSE WORK!!!

I can't keep the bedroom doors closed otherwise air doesn't circulate.
I picked up a fantastic tip from a cat behaviour book that cats HATE
walking and sitting on Aluminium Foil ("Tin Foil" or "Baking Foil" in
the UK - daft cause there's no Tin in it!). Cats also wont walk on
double sided adhesive tape, but you can't put that down everywhere.

The Aluminium Foil things works. If there is a surface I don't want the
cats walking over, I'll cover it with Aluminium Foil. I even made a
roll of double news paper sheets with foil glued with a glue stick to
the news paper and it's the entire length and width of the stairs. That
should stop them but there is no accounting for the call of the wild!
They will battle up the stairs, trying to push aside the foil but I
hear them. I just shout "DOWN!!!" (Off or Out) and they know what it
means!

Tonight, however. I couldn't be bothered fannying about with baking
foil and news paper so I set up a few flat packed boxes from the move
as a barricade on the stairs.

The little buggers! they both totally and stealthily got over it, I
hadn't a clue until one cat came home. The other was on the flat roof
and over a wall and on another roof. I tried calling her, rattling a
fork and an opened can of food, rattling a box of crunchies and even
dancing a spot of red light from a lazer pointer they both try to catch
sometimes.

I might as well have not been there, not a single bit of notice did she
take, it was so infuriating. The whole thing is maddening as hell. They
know and remember my reaction if I catch them in the bedrooms or on the
stairs, they turn round and run like hell. SO WHY DO THEY KEEP DOING
IT???

You can't get it to stick like you can with dogs.

Short of chicken wire across the window I don't know what else to try.
I can't put locks on the internal doors - tenancy agreement and they
are not heavy, the cats can jump up and push them open easily.

Should I surrender?