Bath Waste screw turning but not coming out

[Stevil]

Nothing technical about this problem but it is a pain at the minute for me.
The bath waste has become loose and is leaking water, I've tried tightening the retaining screw but it just turns without ever feeling tighter, I thought I'd remove it and replace it, but again it just turns and won't come properly loose.
I'm guessing there's a captive nut and that has either ceased to be captive or the screw or nut has stripped its threads.

Is there any easy way I can remove this? I have the bath panel off and access to the underneath, and I suppose I could try to get a pair of pliers up inside the waste from below to grip the nut, but as I can't see inside the waste from below I'd be groping in the dark.

My only option seems to be to go in from above. Is there any other option than drilling out the top of the screw? Sod's Law dictates the drill will slip and puncture the bath!

Any and all suggestions gratefully received.

 

[sircerebus666]

As you're removing the waste simplest is way to cut the plastic waste away under the bath to expose the screw

No worries about damaging the bath that way

 

[terryplumb]

Get second person to pull downward on the waste fitting below the bath whilst you unscrew from above ,good chance it will come apart.

 

[Madrab]

Is it a standard waste with a plug? If so, do you have a pair of wire side cutters?

 

[Stevil]

Hmmm some useful suggestions there:
I should be able to hacksaw the waste from underneath,
At the moment I don't have a second person to lend a hand with applying force while I'm turning the screw, apart from my kids and I doubt they could apply much force to be useful.
Side cutters? I'm not sure, I've got some long-nose pliers that have cutters built in but if you were thinking of cutting away the metal from above, I had imagined this would be too strong for cutters . It does look like a standard waste to me, it's the one that was fitted when the house was built (about 7 years ago)

So assuming I get this done, will I need some Plumbers Mait when fitting the new waste or will there be gaskets/washers supplied with a new kit?
I was just planning to replace it with a bog-standard kit like
https://www.screwfix.com/p/bath-waste-with-plug-chain-16/91024#product_additional_details_container

 

[terryplumb]

Can you post pics of waste beneath bath ,and from above ,?

 

[Stevil]

It was just a bog standard waste like the one in the link, but I managed to get it removed using a combination of the suggestions given: I used long-nose pliers inserted into the drain segment from the upper side, then, while standing in the bath, pulled suface it hard up against the under-bath surface with the pliers, while unscrewing it with my free hand.