Problem Accessing Perch After Moving Server

I've recently migrated my Perch installation over to a new server but can't seem to access the admin interface due to a software update error:

The following error occurred:
DROP INDEX `idx_uni` ON `perch2_resource_log`
SQLSTATE[42000]: Syntax error or access violation: 1091 Can't DROP 'idx_uni'; check that column/key exists

The following error occurred:
ALTER IGNORE TABLE `perch2_resource_log` ADD UNIQUE INDEX `idx_uni` (`appID`, `itemFK`, `itemRowID`, `resourceID`)
SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'IGNORE TABLE `perch2_resource_log` ADD UNIQUE INDEX `idx_uni` (`appID`, `itemFK`' at line 1

The website itself loads fine. The new server is running php 7.0.9 rather than php 5.4.15 on the old server (MySQL version 5.7.13) - I'm guessing it's not a php problem though? Hopefully someone else has had something similar.

Many thanks