Was £2.99 now down to 99p but possibly make yourself a whole penny by using the TCB Reserve&Collect deal. Their 5 litre bottle is £19.99 so you could get the same ammount for a fiver.
* Protects against freezing and over-heating.
* Acts as a corrosion inhibitor and is methanol-free.
* Temperature protection range -36 to +155°C.
* 2-year product life.
* Tamper-proof seal.
Hope this doesn't stop this deal from deal from going hot.