Can I still add funds (or 'top up')?
No. To improve clarity on this topic and ensure there is no shared ownership, the DfT confirmed in the guidance update that adding funds is no longer allowable. If you wish to get a bike worth more than £1,000 your employer must agree to increase their limit.
I can see this being an issue with some employers as they may think that £1000 is already far too much to spend on a bicycle...