We inherited a house too that we rent out - it is in my name for tax reasons, Mr BP is a high-rate tax-payer. We bought out my brother-in-law's 50% share.
We used an agent initially, they vetted and credit-checked the tenants, but after 4 years with the same tenants we took it on ourselves (the agent did nothing for their fee except take the money, deduct their fee then send it to our account after it had sat in their account for a couple of weeks).
As the landlord, I have to make sure that there is a gas safety check every year, I have landlord insurance and I have taken over the deposit which is lodged with the TDS - the Tenancy Deposit Scheme. The gas check and the deposit scheme are legal requirements. We have been very lucky with our tenants, they are nice people who take care of the house and pay their rent on time. I guess using the agent initially helped to get this calibre of tenant, but we paid their comission for years without any further benefit to us. We are getting a return of about 8 - 10% after paying the mortgage etc. You can PM me if you want to know anything else!