Update
I have one of the bigger V blocks as per opening photo sitting in a bucket of diesel, i also put a smaller Eclipse magnet in with it. The smaller one i took out today and low and behold, after a little bit of brute force and ignorance. Its finally moved and now it moves freely and is in full working order. Decided to let the bigger V block sit for a little longer as there was no sign of it moving. Will give it a go tomorrow.