DSA - don't want equipmentWatch
If you don't want the equipment, don't order it. Just let your study needs assessor know that you won't be taking it. Not taking the recommended equipment doesn't mean that you can have £1018 to spend on a higher spec computer. You can, however, contact the DSA team about upgrading on the recommended laptop. You would pay the £200 + any additional costs incurred. SFE will only pay to the supplier the agreed price of the laptop - your £200 contribution. EG, agreed laptop £350 - you pay £200 and SFE pay £150. Upgraded laptop costing £500 - SFE pay £150 and you pay the rest. I believe you need SFE's permission to upgrade, though. You will need to follow their instructions in your entitlement notice.
You can't just have a laptop, upgraded or not, without the assistve tech software. Every student will need a laptop/computer of some kind so that is not an additional need because of your disability.
As another user has said (Lovesick) you won't get the money if you choose not to have the items. That's just not how DSA works.