On Thursday, 30 May 2019 17:16:04 UTC+1, Chris Green wrote:
Can anyone suggest where I might find a large bore 2.5m shower hose?

This is 2 metres

https://www.showerheadhosesmixers.co...t-shower-hose/

Could you use a coupler to join two lengths?

https://www.notjusttaps.co.uk/spares...-extender.html

They also say "We are able to supply special size shower hoses in any length up to 4 meters to special order. Please contact us to enquire." They do 11mm bore in 2 metres.

These people have a number of bores and lengths and say " we are a real company with a real factory where we make and design our products, just south of Birmingham in Redditch" so might be able to handle a custom job:

https://www.byretech.com/acatalog/Shower-Hoses.html

Owain