Bike fit / correct riding position

I have good mobility but rubbish core strength that's come from being scrunched up on my bike being epic and neglecting the gym or other sports.

My physio is suggesting two gym sessions each week 1to1 but there is no way I can afford that, that's £200 per month. Is it unrealistic to ask him for one 1 session each fortnight to be 1to1, then direction or a plan from him for home exersises for the other 3? Has anyone here done something similar?

I have a roller mat and a turbo but no other equipment at home.

This sounds fine to me. In fact it sounds sensible. Work through a plan, do that plan 2 times a week, then get progress checked once a fortnight.

If you're working your core at home. I'd recommend getting a swiss ball.

For my needs (so might not apply to you of course) I do circuits once a week at least.

15 x Sit-ups (on the angled bench)

20 x Supermen (face down, stomach on swiss ball, raising left arm + right leg, then left arm + right leg etc.)

15 x leg raises (on that wierd frame you dangle from your forearms on. Lifting knees to waist height)

15 x back raises (on that other weird frame where you ly forward and rest on your hips, and raise your upper body like a reverse sit-up)

Those are easy, and the numbers low. But once you've done 3 circuits it wont feel so easy. My thinking is that I dont want to add bigger sets or weights, when I'm working my core. I want good form, and to reduce the risk of over doing it.