I did it via the built-in file manager but I used filezilla and it worked, turns out bolt isn't the right CMS for me anyway so this issue is now resolved
for INFO - FileZilla is the only way to upload large files and
x10hosting has Bots on all 7 of its free-hosting servers - that deletes any user files 10 MiB (or larger) in size - that have been on the server (in any folder) for more than about 4 hours - from non-upgraded free-hosting accounts only
###