I dont know much about some of the brands, I installed my own after an excavator company leveled the ground for me, it was my first install and was not too hard as long as you are good with DIY.
Im also going to expand my deck this year, in the plans are a hidden compartment in the deck for my solar cover, which will be a box secured under the deck with drainage slits in it and a hinged trap door in the deck boards to give access, on my existing deck i left one of the posts about 5ft high and drilled and attached wooden pegs for towel hooks.
Most people do take them down, I have never owned one so I cant say if leaving it up will be ok.
All the people around here (Pittsburgh PA) have taken theirs down.
Here is mine, I have new steps in it now and we added a new grill and a swing on the pool deck.
This fall im planning on extending the deck all the way around the pool.
When you add water try taking a sock and stuff it with the batting you get at craft stores then tie this over the end of the hose so it will pre-filter the water, you can also try putting the hose into the skimmer so your fill water goes through the filter before entering the pool, doing both at the same time may help.
You cant reuse a liner, they stretch when you first fill with water on a new liner and when they have been drained and removed they can become brittle plus you have the problem you are having, the liner could stretch too thin in some areas and split.
I cant really speak for the covers you have over there as im not familiar with them, A solar heating system may give you better results as long as the solar panels get lots of direct sunlight, I would guess around 6 hours a day.
Out of interest what type of pool do you have?