Complex sentence: Some consideration was given to finishing the station at Brockley Hill, as it had some housing and the site lay just within the green belt; the line beyond to Bushey Heath would have been for access to the depot.
Split into simpler sentences: Some consideration was given to completing the extension as far as Brockley Hill, as it had some housing and the site lay just within the green belt. The line beyond to Bushey Heath would have been completed for access to the depot.