The "Daiichi" is rather hard to figure. Is it that there is more than one "Services and Support Division," or is that there are several divisions and this is the first of many? Both of these options do not seem to gel. It seems unlikely that there would be more than one division like this, and in the second case, the Japanese would be different.

My guess is that the daiichi modifies the services, i.e. they are "Primary Services," in some sense. Searching on the net I find that this phrase is used in more than one way but particularly with reference to environmental services. See references below.

I think that there are sure to be more than one type of such primary services so I would go for the plural.

I also guess that this is for translation of a real department in a company (for their letter heading, or someones katagaki or whatever) so I would say it is best to stick to a literal translation without dropping words.