Removal costs (eg the people that transport your furniture) are standard rated to you and the VAT cannot be reclaimed.
Re the Annex.. See para 17...
The only other building that you can count as part of your eligible building project is a garage providing...
By that token a small free standing "building" to house your electricity meter should also be standard rated!
If the annex is totally self contained (eg kitchen, bathroom, bedroom) and there is no planning condition that precludes you selling the annex as a separate dwelling, then it should be possible to get it zero rated/reclaim the VAT. That's because it's effectively another house.
Edited by temp, 04 March 2016 - 04:45 PM.