Hi Martyn,
Both the basses I use regularly are Squier Affinity P basses (1997ish). They have been resprayed, a few tweeks, but that's about all. To be honest I agree with you that the difference between the Squier and a more expensive Fender P bass, in my view, does not add up to £500 or £1000. Moreso with a bass guitar where the sound is not as critical as playing a Strat or lead the difference is even less.
As I said in a previous thread the new Squier Classic Vibe P bass in fiesta red/tortoiseshell combo at about £279 is all you can probably wish for, good looking and well priced. I would try that as a starter. Machineheads, pots and maybe pickups are cheaper versions on the Squiers, but my two go back to 1997 and there have so far been no problems with either, if you want to upgrade these bits you can do so.
Also if you buy a Squier you can easily upgrade it to what you want, but buying an more expensive Fender you would be spending a lot more to upgrade that. The Squiers also have the truss rod adjustment at the headstock which I prefer, rather than the bottom end so you don't need to remove the neck every time you adjust the fretboard, which is quite useful, as I think a bass neck bends quicker than for eg a Strat.
I must sound like a real old scrooge, "try before you buy and as cheap as possible, already!".
Anyway welcome to the world of bass and let us know how you get on, we are all dying to know what the new Fiesta red Squier is like so if you go for one we all expect a full and thorough report.
Now what did Roger Allcock say about bass playing ?
Regards, Luigi