I'd go number 3 also.
A degree means you have backup in case something goes wrong. I agree with JB about degrees - do one you enjoy! Otherwise, you'll lose interest and it will show in your marks. I don't think there is much of an advantage from an aviation employment perspective with regards to which degree you do although an aviation one may potentially 'better prepare' you for the later stages of your training.
Whilst at university, you could join the RAF Air Squadron where you'll gain flying experience there (not sure if you can fully complete your PPL with them but I'm sure someone more 'in the know' will confirm this).
Either way, your first 2 years at university are fairly easy going so you could afford (time wise) to get a part time job and pay for PPL lessons as you go (1-2 per month seems reasonable). However, you'll have to be good at money management otherwise you'll have no chance [insert beer smilie 
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There is no way you'll be able to get any further than PPL at Uni - the final year is a challenge and you'll want to work as hard as possible to get a good classification (otherwise there's no point in going in the first place).
After this, get a graduate job and continue to fund your PPL. Then, if you're enjoying it and know it's for you, get a class 1 medical and begin to study for the ATPLs / hour build.
Food for thought - a degree isn't the be all and end all. You could simply get a job at the bottom (99% graduates start here anyway) and work you're way up. There are loads of people here who've done this.
Good luck - p.s. I know everyone says it, but you'll have the time of your life at uni.