Starting issue

[Chris_90]

I've got a strange issue that I've never come across before. 

I do Alot of stop start driving car stays hot. When I come to start it it's like the battery is flat turns over really slow but if I wait 30 seconds for the glow plug relay to click off it'll fire straight away. I thought it was the battery so bought a brand new one but still same issue it's like the glow plugs are sucking all power. 

I've done the same driving style on many xud's but never come across a problem like this before. 

Car in question is a citroen bx.