I am taking the liberty of pasting below some interesting background on the reason behind the move of the county archive and local studies from Trowbridge to Chippenham.  It was left as a comment on my blog post about Access to Archives by John Ellis.  The full post and comment can be read here:

http://tehmina.org/2007/06/12/access-to-archives/

"As a strong and active objector to the move of the Record Office from the superior accessibility of the County town, I can assure everyone that transport, especially from Salisbury, where I reside, was very strongly represented during the consultation exercise. The Leader of the Council when the project as mooted said a new bus service could be arranged. That was a ridiculous response because it would have been uneconomic and dependant upon appreciable subsidy.

Typical of the irresponsible way that the project was conducted the comparisons with other possible locations was skewed in Chippenhams favour as were other important factors. The determination of the subsequent and current Council Leader to bag this facility for her home District was little short of dishonest.

She was warned that the Lottery grant of around 50% of the cost would not be forthcoming if the Chippenham site was selected was misinterpreted by her officers and ignored when it was drawn to the Council’s attention.

t was not just the transport factor that was behind the Lottery decision. The Chippenham site was to be on a former cattle market made redundant for the purpose to the consternation of the farming community. Designated the biggest cul-de-sac in Europe, it had just one access road from the clogged town centre and bounded everywhere else by barriers of the London mainline and redundant railway embankments plus a river. The building was to have its main entrance within the danger area of a major electricity site with transformers which presented an explosion hazard known throughout the country.

A last point for this sumary is the fact that volume records from Salisbuiry District and its Diocese (which includes much of Dorset but not Chippenham) exceeds the whole of the rest of Wiltshire and Swindon put together!"

I used to live, or rather I grew up living in that big cul de sac 
I do not know much about why the decision was taken to locate the records office in Chippenham, but I do know that it was a joint project between Wiltshire County Council and Swindon.  I do have a contact who knows much more about the whole subject that I do but I do not wish to put their name in the public domain.  Some people say that Swindon Borough simply consider Chippenham to be a satellite town to them and of course where is the next easiest place for Swindonians to get to other than in their own town?
There are some real sceptics who think more Wiltshire services could 'head north' when the new super council is created but I personally I dont believe that this will be the case.