I use a ground flax seeds, chia seeds and sesame seeds. Plenty of fiber in combination of water and plenty of activity.
I also make sure to eat plenty of fermented foods.
My youngest has low muscle tone (very common in people with Down Syndrome) and I give her daily soaked prunes (eat the soaked prunes and drink the liquid), a good probiotic and Osmolax.
Osmolax is one of the mainstays of constipation treatment. It simply adds water to the poo which makes it softer and easier to pass. It does not have an effect elsewhere in the body, simply a local effect on the stool. Therefore, it is safe to keep on taking it indefinitely – and some people do.

Try a serving of greek yoghurt each day and drink lots of water.

Maybe go see your GP as you mentioned you had Bowel cancer
My father had Bowel Cancer also and has the same problems

Movicol, prune juice, senna, extra fluid and movement such as running.

I use a ground flax seeds, chia seeds and sesame seeds. Plenty of fiber in combination of water and plenty of activity should do the trick

Nothing worse! Drinking prune juice helps but it tastes awful!

1) Metamucil for a few months/weeks – they recommend 3 doses a day but see what works. Even 1 spoon in morning mixed with water might help. You can get different flavours orange or lemon. 2) Switching to wholegrains, brown rice, wholemeal pasta etc. and generally avoiding refined flours. Once you’ve made the switch you might not need Metamucil supplement. 3) Make sure have enough liquid, eg herbal tea every evening. before bed.

metamucil works if you just want something easy to use.
drink lots of water as well,
more fruit, more fibre.

I would up your water intake of you are trying to increase fibre, which a lot of people do to get their bowels moving. If you are having increased fibre and not enough water, then it can actually have the reverse effect and constipated you further. I found a couple of links for you.

http://positivemed.com/2014/10/08/20-foods-act-natural-laxatives/

http://www.oxypowder.com/laxative-foods.html

A small amount of fresh prunes and also plenty of water seems to do the trick. Maybe check with your GP if this is OK?

I would advise you to take one spoonful of fermented food every day, for example sauerkraut. And see if it helps.
Or you could try taking some probiotics.