BS 8515:2009 (+A1:2013 where relevant) has been withdrawn and replaced by BS EN 16941-1:2018, which can be used for new assessments.
The basic approach in BS EN 16941 is equivalent to the intermediate approach in BS 8515 is. The detailed approach is still described in the same way.
The relevant schemes will be updated in the next reissues. 03.11.2021 Issue 2.0 of the UK RFO technical manual amended.