I have Music Creator 6 installed into Windows 7, 64 bit.  This installs TTs-1 fine, but Band in a Box & Sibelius can't see it as it needs to be the 32 bit version.  I can't find a way to load just the TTS-1 from the disk, or to force it into a 32 bit now that it's pre-installed into the 64 bit version, if yuo see what I mean.  I've tried uninstalling the lot and re-installing but there is no option for TTS, even if you select custom install and try and force a 32 bit installation.
Any way to install the 32 bit version somewhere or other?  I do also have a machine running XP, so if I install the whole thing on there can I copy over the TTS-1 from there?

All Music Creator programs are 32-bit only, and that includes the soft synths that come with it, including TTS-1, otherwise they won't work with MC.
I don't have Sibelius or BiaB, so I don't know how they handle/recognize VSTs.
It may be that TTS-1 is a DX synth and not a VST.
Just checked my SONAR program, and the TTS-1 I have is a DXi, not a VSTi.
It may be that you have a VSTi and a DXi version of TTS-1 and you're trying to load the DXi and not the VSTi.
Check your Plug-in Manager to see if you have 2 versions of the instrument.
And welcome to the forum.

TTS-1 is DXi only. Depending on the CW DAW installed, it will either be the 32 or 64bit DXi. DXi synths may run in VST only hosts if a DX-to-VST wrapper like http://xlutop.com/buzz/zip/dxshell_v1.0.4b.zip is used.

In Band In A Box, you have to manually install TTS to be it's default synth. It's not an automatic thing just because TTS is on the machine. It's been a very long time since I did that install but I do recall it simply being a matter of telling BB to use TTS and choosing it from the list.... Same thing with real band if you have that too.
 
I do remember that I did not have to reinstall TTS. It was there already from MC ...all I did was locate it and install it to BB