I think RR is about the same as having BWD.
The Rebels have visited Poole 3 times this season as you know. Where BWB has rode in 2 scoring 5 and 5, both from 5 rides as you say, although he fell in 1.
Lawson takes a ride...2 meetings this year scoring 7 from 6 rides and 8 from 4.
Summers has rode twice, scoring 2 points both times.
Covatti scored 5 and 6 from 5.
Allen has scored 6 and 2.
I would expect 5 points from his replacements.
Of course anything can happen.You only have to look at MPT's 18, the time before he scored 6 from 5 at BV. They might score 7, they could score 3.