and no you dont need solicitors
and you certainly dont need a solicitor to do it
see other threads
and kick off at the MCOL site here
https://www.moneyclaim.gov.uk/web/mcol/welcome
if you goggle MCOL the fourth quoted is one of those 'falsies' - a look alike site that charges for use
oh and by the way the solicitor is witness
but will quite naturally charge around £200 / h for his time what you can do yourself
if you want the other side to do something inthe contract and he hasnt then you will need 'specific performance' and will beed help for that one