I think if you only want to spend 1k you might end up with another turkey
if you are doing 36 miles a day, a turbo will cost about £8 - £10 in fuel, so about £200 a month in fuel
if you can afford £200 a month in fuel and insurance, buy a cheap diesel and run that for 6 months or so and then save up. if you have 2k more you will be able to find a decent one, with decent history and has been looked after, and it will have less chance of being a turkey
no offense to anyone, but some of the 1k cars will be bought by council estate cru wanting summat well fast innit. and then when it comes to maintenance or mods, corners and costs are usually cut. 'my mate says it doesn't need a remap, cos it's got a self learning ecu' or 'my mate can remap it for £50 and it will be well rapid bro'