I usually get money transferred to Thailand with World First. They have just notified me that their fees will go from $0 to $40 per month on transfers under $10000 So I wish to change companies. 

Previously I've seen the most people use another company but I can't remember the name.

Can anyone recommend a good company please?

Transfer wise, now Wise

They were transferring USD or making the change to Thai Baht prior to transfer?  Suspect the latter and that was paying for the service (bad exchange rate).

Transferwise (WISE) will require payment for each transfer and the deposit will be in baht - but they advise exchange rate when you start transaction and it will be better than even the Thai local bank rate (used when funds are sent in USD).  

If you need these transfers to prove income there are other factors involved - best to use Bangkok Bank account and select reason as long stay in Thailand to be sure deposits are recorded as foreign source.