I purchased a laptop last year with battery that lasted for over 2 hours. However, recently it is only lasting for about 30 minutes. Rather than forking out £120 for a new battery, is there some way I can 'condition' my current battery.
I agree with AubreyS; it sounds that the battery is on its way out.
I read this here about Li-ion batteries:-
"Is the Li-ion a better choice? Yes, for many applications. The Li-ion is a low maintenance battery which offers high energy, is lightweight and does not require periodic full discharge. No trickle charge is applied once the battery reaches full charge. The Li-ion battery can stay in most chargers until used. The charging process of a Li-ion is, in many ways, simpler and cleaner than that of nickel-based systems, but requires tighter tolerances. Repeated insertion into the charger or cradle does not affect the battery by inducing overcharge.
On the negative side, the Li-ion gradually loses charge acceptance as part of aging, even if not used. For this reason, Li-ion batteries should not be stored for long periods of time but be rotated like perishable food. The buyer should be aware of the manufacturing date when purchasing a replacement battery. Up to 1000 charge/discharge cycles can be expected if used within the expected service life of about two to three years.
Because of the aging effect, the Li-ion does not provide an economical solution for the occasional user. If the Li-ion is the only battery choice and the equipment is seldom used, the battery should be removed from the equipment and stored in a cool place, preferably only partially charged".