The usual advice is to wait until you've played 3 games renting equipment, once you have your UKARA buy a RIF of your chosing without having to buy a two tone pew. This'll also give you a chance to see if you enjoy the hobby before you remortgage your life away.
https://ukara.org.uk/
Player registration is free, to become a registered airsoft player you are required to take part in three games at the same UKARA registered game site over a minimum of two months, e.g. the third game being 56 days or more after the first.
You must be over 18 years of age, live within the UK and able to provide identification such as Passport, Drivers License or Bank Statement.