Fastfordman

If you can prove the builder caused the damage and they don't deny it, then put it in writing to them requiring them to sort it or you will get an alarm specialist in and knock off the cost from their bill. If the builder accepts this no problems let them finish the job, if not then you could consider asking them to stop the works and withhold some monies to cover the repair. In terms of insurance any reputable builder will carry public indemnity insurance, but the excess will probably not make it worth them claiming for the cost of the alarm repair.

Most hire companies will only hire to the trade and all will want proof of your own insurance or for you to pay for theirs. If you have a builder doing the work, why can't he arrange his own digger? £150/day with a driver sounds a fair price to me.

A standard single drop crossing will cost £800-£1000 and as mentioned the company needs to be on list of council approved contractors. £2500 for labour is way too much unless your drive is huge. Expect to pay in the region of £500/day for 3 men as a guide to labour cost. Materials wise depends on what you want blocks etc can be bought from any builders merchant but it might be cheaper for a company to buy them as they get big discount of list prices. If you're having Tarmac then the suppliers won't really deal with individuals.

For someone looking to buy materials for a one of job with no trade account expect £100-120/m3 of concrete delivered (c30 or c40 mix would be best) and for mesh 2.0m x 3.6m sheet a252 mesh £40-50. Remember you need 20% more mesh than the square area as you need to overlap the joints and tie them with wire. Please add vat to all figures.