Bad idea not to use agents for overseas landlord?

Letting Agents

I am a first-time landlord so don't have much experience. 

I thought I had to use an agent, regardless of living abroad or not, but their fees are giving me second thoughts. 

The property is in Surrey and most agents charge around 10% of the rent for letting only; not to mention other fees they will charge on top (s.a. setup fee, inventory, references)! Oh there is the renewal fee as well. It doesn't feel it's a good value for money!

Then I heard of OpenRent whose fee is more much reasonable to me but have seen both good and bad reviews on this forum. 

Currently the property is still on the market via a local agent (letting only) but I am really thinking about not using them and going with OpenRent. The only thing that puts me off is that I am and will be overseas most of the time. It seems that OpenRent can do everything even viewings and I was going to self manage anyway once it's rented out. 

So I want to ask the agent to take the propery off the market and use OpenRent for advertisement and viewings; maybe their reference checking service too (but unsure on this one yet). Without the agent, I can reduce the rent slightly.

Is there anything I might miss that makes it a terrible idea?