Do heed the requirements of FCL.710 though:
FCL.710 Class and type ratings – variants
(a) In order to extend his/her privileges to another variant of aeroplane within one class or type rating, the pilot shall undertake differences or familiarisation training.
In the case of variants within a type rating, the differences or familiarisation training shall include the relevant elements defined in the operational suitability data established in accordance with Part-21.
(b) If the variant has not been flown within a period of 2 years following the differences training, further differences training or a proficiency check in that variant shall be required to maintain the privileges, except for types or variants within the single engine piston and TMG class ratings.
(c) The differences training shall be entered in the pilot’s logbook or equivalent record and signed by the instructor as appropriate.
Which means that, for example, if you flew a C152 for your PPL course, then before you fly a C172, PA28-140 etc., you are
required to undertake familiarisation training (or difference training if the variant has certain specific features). So you may
not just hop in to a new variant and fly it without at least some familiarisation training.