Service Agent

We are looking to appoint a Service Agent to help us look in detail at our options/costs/benefits looking forward.  This includes (1) working out what the break charges are with Odlays (2) the market value of our property with and without the lease in place (3) potential net rental income with a different management agent outside the lease.  I have found someone who will do this as well as handle any/all correspondance or actions related to the property.  I have found someone working under French Property Consulting Ltd - the fees are £500/quarter and wondered if anyone has worked with them and can provide and feedback and/or any other recommendations or benchmarks?

Thanks in advance for any tips/guidance.