We cannot do what you ask. We cannot predict the future (as much as we would love to be able to). Prices change daily in the computing world. £1500 laptops now will be worth circa £700 - 800 in September or replaced by newer faster machines completely.
Laptop adapters is pointless to look at as they vary in price depending on what laptop you have. Power consumption and the power connector vary between laptops so while 99% of laptops can be probably be run off one of these there is still the chance you will end up with one that wont work on yours. Best to tell the IT department that you cannot do what they want just yet. Maybe come July or August. But not a hope in February.