Tsukamaki, Sageo, and Fittings
First of all, I do not accurately understand the state of your iaito.
And, I do not understand how you want to change it.
>really I'm looking to change my ito, sageo and fittings aswell...
Does “ito” mean “tsukamaki”?
If yes and your tsukamaki is normal, you can purchase tsuka-ito and wrap tsuka by yourself. It is not easy, but not difficult to master.
http://www.jogibeer.de/katana/tsukamaki.htm
http://www.n-p-s.net/tsukamaki-1.htm
http://www.n-p-s.net/tsukamaki-2.htm
http://www.n-p-s.net/tsukamaki-3.htm
I have five iaito. 3 tsuka are normal, and 2 tsuka are special.
I re-wrap 3 tsuka by myself on 1st January every year.
2 tsuka are made in Edo period, so I ask Tsukamaki-shi (professional Tsukamaki specialist), Nakamura Ryuji sensei to re-warp them.
Nakamura Ryuji sensei;
http://www.yk.rim.or.jp/~ryusui/into2.html
If it is impossible for you to re-wrap tsuka by yourself, you should look for Tsukamaki-shi and send him only Tsuka.
You don’t need to send the blade and saya.
As for sageo, various kinds are sold with Budo shop.
However, sageo is merely “kumihimo”(braided rope).
You can find several thousands kind of kumihimo in a kumihimo shop and you can purchase about 2 meters of kumihimo.
http://www.braidershand.com/
Moreover, there is a lot of kumihimo in all over the world.
Maybe UK has kumihimo as a traditional craft.
Off course, it is available if it is thinner than kurikata hole.
This month I visited London and Cardiff for bussiness, but I don't have any information.
Sageo is not expensive even if you ask for the custom-made-manufacturing.
She is Hanayagi Yaemari sensei that produced my sageos.
Hanayagi Yaemari sensei;
http://www.ne.jp/asahi/kashin/hanamari/kumihimo.htm
It is necessary for iaido learner to learn handling the sword itself.
The person who practices iai should have the knowledge of simply adjustment and the repair of the sword.
Mai Shikata
If you want to strike your opponent, you should let him strike at you.
If your opponent strikes at you, he himself will already have been struck.
-- Yagyu Munenori