Hi!
Yes.We are a London based resurfacing company!
I personally resurfaced hundreds of old baths!in a past 10 years
so I can say I know something about resurfacing!

The method posted below is when you have to rip out the bath and take it to a workshop,(which alone can turn in to a nightmare as a cast iron bath can weight over 350lbs),
where they rebuild the vitreous enamel coat from scratch!
No doubt this is the best way to restore!but
Is cost nearly as a brand new around £2500!
We can offer you another solution which is going to take away your problem at least for a next 5 years!as we give you a 5 year written warranty!
We use a very high quality,durable,hard wearing enamel system!polished to a mirror shine!Leave the bath smooth,and easy to clean,just like new!
cost around £300
You can contact us here!
http://bathresurfacingspecialist.co.uk/