Hi Dave,
You could use silicone hose. The hose needs to be 5-6mm ID.
For the moment what you could do is to pull a little more through the pole, cut off the last few inches. Slightly heat the hose in hot water and push it on fully to the end of the 'Y' piece. Then use either a small Jubilee clip or an 'O' clip to fix it on (make sure that you slide this onto the hose before fitting to the 'Y' piece). That should take care of the situation.