TBH I would never fanny around trying to repair a broken pump, buying spares etc etc. Who has the time for that? Time is better spent out cleaning windows and earning money.
If you spend 3 hours trying to repair one, that's about 3 x £30per hour = £90 before you've even paid for any parts.
Just spend the £130 and get a new one. Actually get 2, because IMO you should always have a spare pump on hand. It's one of the few things that can stop you working.