Red mason bee tubes

[snakeshack]

I bought 2 mason bee houses several years ago at a show made by c j wildfoods (?) which have been very successful and have had all the tubes filled for the last couple of years, one attached to the shed at the allotment and the other cable strapped to my chicken coop at home.
The lined cardboard tubes are now becoming dirty and in some cases soggy at the bottom of the nests and I would like to replace some or all of them when the bees emerge (about now).
can anyone suggest a supplier as I am having trouble locating one and don't want to saw up yards of bamboo which probably has the wrong diameter internally for my species.

[Guest]

^^^Red Mason Bees | CJ Wildlife (UK)

[snakeshack]

thanks for that ,due to a "special offer it is cheaper to buy two new nesting boxes than to replace the tubes