Is there also no difference, if so far only one brings profit and second one loss?
This is where it starts to get complicated. If both trades are conducted on a commercial basis and with a view to the realisation of profits, then there is indeed no difference. But if one source is non-commercial, there might be an argument from HMRC that the losses can only be carried forward (as opposed to used "sideways" against the other source) against future profits from the loss-making source.
Bottom line is that you need to carefully consider whether this is one business or two. To be honest, I'm not sure ...