Thetford C402 spare part required

Hi, can someone recommend an online supplier of a Thetford Cassette C402 spare part please. I am after the concertina rubber connector for the water level viewing tube. I have checked online, but it appears it comes as part of the complete kit shown in the photo below. I am happy to purchase the complete kit as a spare for our travels next year. The rubber joint on ours looks weak and flimsy and I want a spare in case it starts to leak in the future. Water leaking in the area around the bottom of the door could be devastating. I sealed all round the bottom of the Thetford door entrance, soon after we bought the van new, as I was amazed too see gaping gaps into the construction! All dry so far.

I have found this kit being sold online by suppliers in Holland and the USA, but not in the UK. 

Can anyone help please.

Pete

This one? https://www.leisureshopdirect.com/water/caravan-toilet/thetford-cassette-toilets/thetford-toilet-c-402c-cassette-and-spare-parts/thetford-c402-drain-tube-rubber-elbow

Thanks Peter, I went on their site and did a search but didn’t come up with anything, probably using the wrong link phrases!  

Brilliant, thanks again.

Pete