Easily have it done, we stripped my engine one night, and rebuilt it in another, including valve stem seals etc, We did finish at about 4 am though! Did you ever find the cause of the problem Taggy? Look forwards to seeing this again!
Toyota red last year wasn't too expensive, this year I went and they wanted a fortune!! So this year I've been using red coolant from my local motor factors and mixing it with water 50/50. (Make sure it's the red stuff and not pink or blue)
Bridge te1 and t1 (double check) on your diagnostic port, this will then give you a flashing sequence on the engine management light. (For example,. Flash Flash Flash.... Flash Flash................Flash Flash...Flash Flash Flash.........) That would mean 32 and 23.