Tips for hiring a reliable home letting agency

You will find that it is the day to day management that is problematic, who lets them in, who cleans and maintains the property. Many owners do that personally if you are paying an agency it will be expensive and open to disagreements.

If you trust your friend's recommendation, I don't see that there is much more you can do. The letting agencies usually arrange the cleaning staff. This is why agency letting is expensive and holiday cottages are expensive.
The alternative would be keeping a close eye on it yourself. Find a local person to be your own agent.

We've rented the same cottage on a Scottish island, a few times, from a family who live in the South of England. They themselves visit twice a year and rely on a local woman to take payments on-line and clean between lets. She looks after a few cottages - and the doctor's surgery. We had to stay over our time while we waited for the ferry and she came in and changed the beds and checked everything, in record time.

But I have heard stories of holiday lets being left in a mess so it is a chancy business.

I’ve friends who used an expensive but reputable company.
They put a visitors book in the property, collected all the email addresses to create a data base then after a couple of years went solo!

The issue we found letting out an overseas property was everything started well but as time progressed we found they get very lazy . As weren’t there or likely to pop in unannounced they got away with murder.

We turned up unannounced once and it took 3 days for them to call us and say there’s someone in your home. We parted company with them shortly afterwards!