I rented a flat through Guy Salmon Estates for approximately 2 years and unfortunately I cannot recommend them at all. They were slow at making repairs which ultimately resulted in a water leak causing significant damage to other flats and costs for the landlord. Even for minor repairs they had to be called almost on a daily basis to manage them.
It was generally a reason to celebrate if they showed up to agreed appointments. Even when I moved out, they failed to show up and I had to hand over my keys to the new tenant without the estate agent being present. During my entire stay, they never completed a move-in checklist (which I ended up doing myself!) and never checked the state of the flat when I moved out.
When I finally (!) left the flat, it was perhaps unsurprising that they never registered my deposit with a tenancy deposit scheme. Since my contract said that this was paid to the landlord, I eventually had to file legal charges against the landlord to receive my deposit. During those discussions it became clear that the landlord never actually received the deposit, meaning they had to pay it out of their own pocket.
In summary, I can only recommend to stay as far away from this estate agent as possible. Certainly as a tenant, and (from what I have heard) also as a landlord!