Male cat urinating everywhere!

My male cat Santa who is 3 on Christmas day (as if the name hadn't given that away lol) is peeing everywhere!  When I moved to my new flat 2 years ago I thought it was down to nerves and change of scenery till he settled in.  My front room started to stink as he would be all over the carpet and no amount of products, cleaners etc stopped him.   I live in a rented property so without telling the landlord I paid to have the carpet replaced at a cost of £200.  All ok for the last year and he stopped weeing on the carpet and just using his litter trays.

These last 2 months he has started doing it again and I have no idea why! I live in a first floor flat and the people below must notice the smell and will start complaining.  I am a very houseproud person and always tidying, hoovering, mopping etc so this is getting to me.    His favourite spots are behind the tv table or behind my recliner sofa which also now stinks as soaked in so will need to get rid of that when I have the money.

He's been done so not that, not ill in anway, happy and affection, eating and drinking as normal.  I change the litter everyday which costs me a fortune but sometimes makes a difference and no weeing for a few days but then back to doing it again.  I use expensive enzyme urine destroyer that costs me almost £20, this one currently http://www.petsathome.com/shop/en/p...-odour-remover-for-cats-4-litre-(online-only)      I've tried the Bissell one too.     I've done the rips of using bicarb to soak up the urine.     Nothing works and I cannot afford to keep replacing my carpet.   I walk into my front room and it smells of tom cat wee and it's really getting me down and making me paranoid especially as I am due a flat inspection soon.   

Does anyone have any advice on what I can do or try to get rid of the smell or stop him doing it in the first place please?

Do you mean "he's been done" that he's neutered?  As you also mention your place smells like tom cat pee which leads me to believe he's not neutered?  If he is not neutered that should be done ASAP.  The smell of tom cat pee is over the top.  Once neutered the strong odor will leave, but it seems as though he might be doing territory marking.  This could now be a habit. Also cats are very good at hiding that something is wrong with them.  Have you had him seen by a vet?  That should be step one. 

As for cleaners, a good enzymatic cleaner should do the job, but you might be missing spots.  Get a black light which will help uncover missed spots.

How many litter boxes do you have?  How often do you clean them?  I would scatter litter boxes wherever he pees, 1 near the front door, 1 behind the tv stand and one behind the sofa.  You can get a product called Dr. Elsey's litter attract.  It has special herbs in it that attract a cat to the litter box.  Also is your litter box covered or uncovered?  How big is it?  How deep is the litter?  All of these are important.  I will a video from the cat guru, Jackson Galaxy.

This is THE most frustrating thing, with cats.  Makes me NUTS when they do this.

I live in a house, not a rented apartment, so my solution won't work for you.  I had to remove all carpets, even throw rugs.  I have hardwoods and linoleum only.  Three of the pets I've had over the years thought rugs were for peeing. 

Interesting that he was good for about a year.  Try and think what changed to make him start again.  Did you change the brand of litter you were buying?  Did you move the litter box to another location?  Did someone move in with you, or move out?  New friend started staying over?  Did another cat move in to another apartment in the building?  Oh yes, they KNOW this!

I feel for you, don't really have much advice.  I do hope you get some good results.