Can you get a closer image of the white stuff please? From this distance it is not easy to see.

Could it be bird poop?

I notice there's a vertical crack in the trunk in the top picture, with missing bark and a white mould like deposit at the base. Where the smaller white deposits are higher up, in the branches, as shown in the second picture, are those smaller branches arising from that particular damaged trunk, or from a different trunk?

Have tried to post a picture of white stuff a bit closer thanks

Don't think it's bird poop.yes I think it is coming from the main trunk. I will check again tho.

Could be oyster scale. Is it rather like cotton wool with black underneath? Otherwise it could well be a fungal infection of the trunk which does look rather damaged.
Personally, once the bush has finished flowering, I would be inclined to remove that section of the bush altogether, right back to well below the missing bark.

Agree - you need a sharp pruning saw to remove that trunk with the white mould on it completely, as close to the base as possible, preferably without damaging the other trunk which arises by its side.

Thank you.I will remove the trunk after flowering.