I worked at Ocklynge for a few years and my oldest is about to leave Yr 6, and my middle is due to go up from Pashley - both schools have been absolutely brilliant.
Please don't be put off by Ocklynge's size - the classes (at 33-35) are no bigger than anywhere else, and my children have only benefited from the extra facilities that the school gets.
The Ofsted report was 1's all the way - the head bought us cream cakes to celebrate! and the atmosphere for both children and adults is amazing.
As a junior school, they have their own swimming pool, and specialist music, rugby, swimming, cricket, football, and tennis teachers - an enormous chess club and choir, 4 link countries, they teach Spanish and ICT - I just think it's a fabulous school.
St John's has a good reputation, but as a church school, I've found them to be bordering on the rude to enquiring parents, and although a lot smaller, it has had some bullying issues as it's a 'primary' as opposed to separate infants and juniors.
Pashley and Motcombe are similar, and I know both schools have teachers' children there, and I don't know anyone who's not had a positive experience.
My own DS had a bullying problem at Pashley, but once it was identified, and he moved class, everything settled back down and he's been really happy.
I would go and visit them and then you'll be able to form an opinion, and if in doubt, pore over the Ofsteds. But Eastbourne is really quite well served for schools, and I don't think there's much difference in the service received from the schools themselves - although some are struggling because of catchment areas, they all work very hard!
Hope that helps!
(By the way - I was a Music Teaching Assistant at Ocklynge, I went to Trinity College of Music, and have returned to 'cello teaching as it pays better - I loved working there, and miss the whole staff and school!)