My car sits on the drive now for weeks at a time without moving. 
 

Is a trickle charger a good idea and can you recommend one? It would need a decent length of cable. 

I have a CTEK MXS 5.0 unit, good quality bit of kit and haven't had any issues with it, you can also buy CTEK extension cables if you need them for the connector side.

Mine has been on a 'project car' for around 8 months and battery is completely fine, it does get unplugged for a few days now and then but is mostly connected.

 

Another option is the solar trickle chargers, these are ok if you can get them positioned in the sun/light and buy a good size one. It also removes the issue of running cables from the car to the house etc.

1 hour ago, the_worrier said:

Is a trickle charger a good idea

Yes. From what you say, think about a solar powered charger rather than a mains unit.

+1 on Ctek - nice quick release connectors, waterproof and good. I have multiple connectors for mine; a cig lighter one for the car where it's permanent live, then a fixed pair of M6 rings I will shortly be attaching to the wife's. I have an MXS7, it's a decent unit. Wasn't cheap, mind...

+2 on Ctek, I have 2.

 

you'll find these branded by some prestige manufacturers as their own to sell to their customers at an inflated price i guess

 

Angelo

I have bought a RING smart battery charger that has a winter maintenance  mode and its compatible with EFB,AGM,lead acid and gel batteries, it gets cracker reviews and it was half the price of the ctek chargers, I will start trying it soon as the weather gets a bit more colder, i've had Ring car products before and they last for years.

Anybody got any links for UK purchase?

Halfords do quite a few, both Ring and CTEK products as mentioned above.
If you can a few weeks, the black friday sales will kick off and you could save yourself a few quid  

2 hours ago, the_worrier said:

Anybody got any links for UK purchase?

Large South American River sell at least 30 different models.