Xela:
These are not Toslink plugs but RCA plugs. I am surprised they seem to be attached to a two core speaker cable at the back. RCA plugs are usually attached to a screened coaxial cable.
In addition to XLR inputs sockets, the TS8 has two (or stereo) line level input sockets at the rear, what you see as red and white RCA females. This is what you have to use for connecting to your system.
If you are using a stereo pre-amplifier, they have L and R line level outputs. You have to take two screened cables with RCA plugs on either end, and connect the preamp L to the TS8 L, and the preamp R to the TS8 R.
If you are using a AVR (which is the most possible case) your AVR will have a SINGLE subwoofer out that will also be labelled as LFE out. Take a single screened cable with RCA plugs and connect this LFE out to EITHER the L or R of the TS8. It does not matter which. You have to do something important now. In your TS8, there is siwtch labelled LFE Mode. This has to be switched to ON position. Now you are ready to roll.
If you are feeling uncomfortable that you are using only one input socket in the TS8, use a Y cable. This cable will have two RCA male plugs on end end and a single RCA female socket on the other. Connect the male plugs to the R and L of your TS8. Connect a SINGLE screened cable with RCA plugs from your AVR to the female socket of your Y cable.
Tannoy may have supplied you with a Y link. If not, you can buy it from any good shop.
Do not use speaker cables. Used screened coaxial cable specially made for sub woofer usage.
Cheers