Next level

Hi Guys,
A few notes

-I'm 34
-6 1"
-218lbs
-I have a very active job
-Over the past 3 years I've lost 5 stone
- I work out at least 4 nights a week if not 5 work permitting. My split is usually Chest, Legs/Back, rest , Arms, legs/abs, then I'll usually do upper body it varies as sometimes I work late and I might not be able to workout at all.

- I'll be the first to admit my cardio isn't the most consistent , I'll try to do 30 mins steady state on stationary bike after working out or HIIT sessions of 15 cycles of 20 secs flat out with 60 secs rest.

My diet is consistent from Monday to Friday during work

Breakfast
Bowel of porridge
4 whole eggs
Protein shake w/ skimmed milk

Meal 1 and 2

1 chicken breast or tin of tuna
Sweet potato
Veg broccoli , spinach maybe some kale

Dinner
1 chicken breast
Mixed veg
Sweet potato

Pre workout - BSN nitro

Workout

Post workout -
Protein shake w/ skimmed milk
Cottage cheese on whole grain crackers

I'll eat fruits and some almonds as snacks and maybe a few custard creams

At the weekends breakfast and dinner are the same but in-between meals are more inconsistent.

When I add up my calories it's approx 800 calories off my maintenance intake.

I'm not looking to get down to single digit bf just lean enough so my muscles are defined with a manageable diet. I've hit a plateau with losing some fat around my waist. It won't shift, why ?

- inconsistent diet?
I've search a lot of online articles and I don't see my diet being that dissimilar to those on Bodybuilding.com or those recommended by reputable online trainers ie rob riches , Scott Herman do I just need to be more consistent at the weekend

- body in starvation mode , is a deficit of 800 calories too much , has my body gone into starvation mode and is holding on to precious body fat because it thinks I'm starving myself . Do I just need to hit my maintenance cals for a few weeks and gradually reduce them to break my plateau.
- not enough cardio, cardio sucks ! I'm struggling to get into a routine of cardio , I never go over 30 mins as a rule I was going to start fasted cardio first thing in the morning. A few experts are saying fasted cardio is counter productive , especially if you are looking to retain lean muscle ?????
My head is fried at the moment , I'm happy enough with the way my body is looking especially after being so overweight. However I've got to the stage where I want to take it to the next level and would really appreciate hearing from anyone that was in the same position. I've seen guys get slated on forums for posting stuff like this so I don't mind someone being harsh as long as theirs advice hidden in there. Thanks guys .