all existing EU subsidies can be continued. Just directly paid from Westminster rather than routed via Brussels.
The other problem is that due to the tax take falling when companies leave the UK, how many and how much the tax take will drop is arguable but it IS happening (not "going to"). the problem not just companies but higher rate tax payers who are not paying tax.
This will compound the problem. So a lot of subsidies will be cut at the same time taxes rise (just to keep the NHS going)