Do I need an L or an M or F VISA?

I am currently in the process of setting up an e-commerce business which will be operating from the UK.

I will be trading with several of suppliers in China and will be also planning to travel to Cambodian as well to see another supplier. One of the suppliers is in Guangzhou and the other is nearer to Bejing.

Basically I will be seeing a multitude of suppliers whilst in china. Do I need to get an Invitation letter for all of them.

Also I have not yet started trading and in the process of applying to register my business here in the UK.

My hope is to get trading agreement between me and the suppliers and get samples of interested goods.

I have brought goods from two of the suppliers before.

My partner goes there often for his work and currently I plan to stay at the hotel he is current scheduled to be staying in, we are not married rather cohabiting. Will this affect what visa i am able to get?

Many Thanks for your help and look forward to your response.