I fully accept what others are saying about the excellence of the MK4 hybrid and I'm in a similar situation to you in that we dearly love our manual 2003 (owned and serviced by me for 14 years, 128,000 miles) but could afford something newer.
There's a lot of benefits to owning an old car.
Depreciation - none, in fact it might even be going up in value.
Maintenance - generally around £30 per year for oil and filter. Tyre replacement costs will be the same on any car.
Running costs - £195 per year for road tax, £220 per year for insurance, average 50 mpg, with 60 mpg on runs.
Possible future costs - clutch, gearbox bearings though no sign of needing those at the moment.
No sign of rust in the sills or wheel arches (have been Waxoyled) which seems more prevalent on 2006/2007 cars.
Goes through the MOT fine every year with occasional advisory.
Suspension parts easily available at reasonable after market suppliers.
No expensive main dealer servicing costs to keep up the service history and protect the value.
No expensive extended warranty to protect the car and especially the hybrid battery.
No worries when parking at the supermarket - if it gets a small dent, so be it.
I keep asking myself what benefits I would gain for my £15k .... and I just can't come up with a convincing argument.
More costs, less peace of mind, more worry...... It doesn't seem a good deal to me.
But that's just my opinion, and everyone is entitled to their own conclusions which will often be wildly different to mine.
Exhaust and cat replaced after theft