Hello Ian,
My first port of call too with regard to the ‘Christmas tree’ dashboard lights would be exactly as Steve advises. In order to give the battery a realistic test, I would suggest you take the car on at least a 10 mile run before subjecting it to a test. If it proves to be suspect, then would I buy a replacement at Halfords? Um! I don’t, but obviously your call Ian.
I alway buy batteries on-line from specialist suppliers such as Tayna, Battery Megastore, Plymouth Batteries - there are more. Most deliver mail order the following day. Incase it helps, I only buy quality batteries such as Varta/Bosch, and only their 5 year warranty (silver topped) grade. Search EBay for your model and confirm suitability with the supplier. With batteries, it’s buy once and wisely in my book. Chances are the new battery will need to be coded to your car - search for a local independent.
Re. shock absorbers:- again search EBay for quality aftermarket ones such as Bilstein ( fit as a pair). I’ve used Car Parts in Motion recently ( no connection, and plenty of others) and found their pricing to be reasonable - just input your reg. no. on their website. Personally, I avoid suppliers who list high % discounts off so called retail prices! You can then enquire at your trusted local garage (or independent) for a labour charge.
Hope some of this helps,
Kind regards,
Gareth.