You should distinguish between:
The capital argument is stronger for expenses relating to the
acquisition of the asset, especially when the expenditure can
fairly be viewed as incurred on the provision of plant and
machinery for capital allowance purposes.
Whether legal expenses incurred in negotiating a finance
lease are revenue or capital in nature has not been tested by the
Courts or by the Upper or First-tier Tribunal. There are tenable
arguments on both revenue and capital sides - see
BLM37015 onwards. If you require any
advice when you have established the detailed facts about the
nature of the expenditure, please consult CT & VAT
(Technical).