Don't give the agents a penny. If the Solicitor representing you is reputable they will tell you this also. The agents will scare you to get you to pay a deposit. Make the offer. If accepted pass your solicitor details to the agent and step back. Because of the worthless £ property isn't shifting. The agent will say things like "paying the deposit will take it off the market" or "you could lose it without a deposit". Utter nonsense
The deposit is there to ensure people who make offers half arsed without thinking it through or realise they don't have the money are penalised for time wasting. I personally have no problem seeing these time waster types losing their deposit if they were stupid enough to pay one in the first place.
I refused a deposit and my purchase went through fine