New Water supply pipe main to house

Water Co alerted me to possible leak and after we checked it turns out that there is a leak between water meter/main and my house. So have to replace (lead) pipe under crazy paving drive (10 m long). A few points I am unsure about. Man from Water Co said it would cost approx £500, there would be three holes and new pipe gets pushed through, so there would not be too much prob on drive. Water Co would give subsidy of £100 and then we would see how new usage comes out. At moment I run at annual rate of 420 cubic meter (three people in house, various guidelines say should be approx 2-220 pa) - when I checked on the meter the dial was moving slowly, at a rate of 200 cub mtr per annum when my main stop cock was turned off. Questions are 1 - is Est £500 reasonable?, 2 - how long back is Water Co going to adjust my usage?
Also: when first inspection occurred the chap switched my stop cock off but forgot to put it back on, 6 hours later our internal supply stopped, after I turned stop cock back on there was lots of air in system, one shower never recovered, had to pay plumber £80 to hoover air bubble out, Shall i claim that?

i would make further enquiries from the water supplier and other sources as lead pipe often gets changed free off charge

yes, read about lead pipe replacement schemes/subsidies, but will they not only replace the pipe? I guess I still have to pay for the digging which really is the main expense
also bit convoluted - having digger, plumber and water co all working separately, very confusing, also unclear how long water supply would be interrupted, esp if so many parties involved that need to be coordinated

We are in the process of swapping out our lead pipe. (waiting on Yorkshire Water)

We've been told they are only responsible for their main and communication pipes/connections, the supply pipe is the responsibility of the home-owner so you're lucky they are offering some towards it.

I've got a builder who will dig a channel in the kitchen floor from the sink then run the mdpe under the sub floors to the front of the house then out under a few metres of flags. Costing around £200, mates rates.

We are looking at the water regs trying to find where it states the supply pipe must be insulated under the floors but have only seen it state fittings must be insulated and even then it's quite vague on what to use.

The water company says they want it 750mm deep up to the house then through a sealed duct and if going into sub floors it must be insulated but where in the regs is this? Would it need ducting in the kitchen concrete too?

The water main must be insulated under a suspended floor up to the internal stop tap. What you do after the stop tap is up to you.
Lead replacement schemes generally mean the water undertaker will connect your new main to their communication pipe for free.

Lots of useful info here:
http://www.unitedutilities.com/documents/1344_How_20to_20lay_20new_20pipe.pdf

All water undertakers have different lead replacement schemes, so always worth checking with them. The Water Regs don't change regionally in England though, they apply to all.

Thanks Bolshy, I'd looked at that one and anglian waters very similar page.

I was hoping to find it in the regs so I would know what thickness to use (my local plumbers merchant stocks tubolit 25x19 @ under £2 a meter but the next size up is 28x25 and is closer to £7.50 a meter.

In the kitchen the pipes* will be lagged and laid in sand but I need to know if it needs ducting too in the concrete floor. *(There will be cold feed to boiler and hot feed back to sink along with water main in in same trench.)

P.S Sorry for thread hijacking

MDPE in concrete should be in a duct. It allows for movement, and for withdrawal to repair. In many cases it requires insulation, so I'd use some anyway. I'd keep the incoming main separate from the services. The 19mm tubolit should be enough for a 25mm water pipe.