Bongo Fury

I can leave my Bongo on the drive for weeks on end without running it and it'll start first time. I took it for a long weekend camping to Cornwall last weekend and it started everyday without fail. On the way home after driving all the way from Padstow to Exeter services, I stop for 5 mins and the thing won't start (luckily parked up next to a lorry driver with a portable jump starter). Get home and leave it for a week - starts fine. Drive to local Wickes last night, struggles to start (although it did eventually).
When it struggles to start it sounds like a flat battery, it tries to turn over but not with enough umpf to get it going. I can often try five to ten times, and then all of a sudden it'll fire up and run fine.
Is this likely to be a duff battery or a starter on the way out? I have recently replaced the battery.

Hi
Starter Contacts, or earth are the likely suspects...also clean the battery terminals. The starter rarely fails, and you can get the contacts on e-bay
http://www.ebay.co.uk/itm/MAZDA-BONGO-F ... 3a814b66a1
For the money, it's worth having in your spares box
Cheers
Helen

as helen says check the earths.
neg battery to the inner wing and the little one that goes from the engine to the chassis rail. they can both give grief.