i only have one space in the underground carpark at my apartment block and will have to rent another. its a prime central birmingham location so itll cost about £100 to park my van at home every month
Needing a second space might not be your only problem - you need to check that you are allowed to park a business vehicle on the site at all. Many leases for flats forbid business vehicles from being parked on the site, or impose restrictions such as no signwritten vehicles or no business vehicles without written permission from the freeholder.
Grabbing a lease I have to hand:
[The tenant covenants] Not to park or leave any commercial vehicle caravan boat or trailer of any kind on any part of the Common Parts nor leave any article whatsoever on any part of the Common Parts.
This one is ambiguous, as the definition of Common Parts given elsewhere in the lease is unclear as to whether it covers the parking space allocated by the lease. That's not the only piece of bad drafting in this particular lease. It seems possible that the lease intended to prohibit all commercial vehicles on the site, but may only prohibit them in shared parking.
The details of this particular lease do not matter - it is the details of any lease or other binding agreement that applies to where you live. If you rent a leasehold flat or parking space, you are limited by the restrictions in your tenancy agreement and by the restrictions in your landlord's lease.