The cold weather won't be helping - the electronic choke will be on for much longer until the engine is up to operating temperature.
To give you an idea, my motorbike has a manual choke lever, and I've not been able to take half-choke off since the end of November, and I do 10 miles each way!

How much has your fuel economy dropped by Boo?
 
Its out by 100 miles per tank. Its due an oil change and air filter. I'm not sure the last time the plugs and leads were done either, need to get hold of Rob but, he is travelling at the moment.
 
I use the A259 to drive to work which, has alot of steep and slow hills which, my wee Automatic doesn't like at all. I have noticed the fuel economy getting worse over the last year.