Number of Associated Companies for Corporation Tax Purposes

Trading Company A is wholly owned by Holding Company B Company B shareholders are 50% Mr Smith and 50% Mrs Smith Other than having the shareholding in Company A, Company B is dormant Company C is a completely independent, non-grouped company which is wholly owned by Mr Smith Am I correct in the following: 1) For determining whether Company A is a large company for corporation tax purposes, there would be no division of the large co tax thresholds as there are no associated companies ? (B is dormant so excluded, and A is not effectively controlled by Mr Smith as his shareholding in B is less than 51%) ? 2) If the shareholding in B were Mr Smith 51% , Mrs Smith 49% then companies A and C would be associated companies and the large company tax thresholds would be divided by 2 when determining whether company A were a large Company for corporation tax ?

Hi Jane Bartlett
For further information on 'Associated Companies'  and 'Quartely Installment Payments for Large Companies' please refer to guidance at:
CTM92520 - CTSA: quarterly instalments: large companies - HMRC internal manual
Thank you