Start with the bathroom you have. London's older homes, think the brick two-storeys near Wortley Village or the compact bungalows across Westmount and Byron, often have narrow doorways, joist runs that limit where plumbing can move, and second-floor baths that need extra thought. Ask any installer to measure the room, check the existing drain, and confirm the step-in height in person before they quote. A low or zero-threshold step-in matters most for anyone with balance or knee trouble, so make it your first question.
Prioritize installers with real accessibility experience over a general renovator who does the odd tub. You want someone who talks easily about quick-drain time, a comfortable seat height for your parent's frame, anti-scald valves, and built-in grab bars placed where they'll actually be used. Confirm they're licensed and insured, and read the warranty on both the tub and the labour. Water sits against a door seal every day, so service response counts. Ask how fast they come back if the door leaks or the drain slows.
Our honest recommendation: hire a specialist for walk-in tub installation in London rather than piecing it together with a big-box tub and a handyman. The weaker path is the cheap online tub plus whoever's available, because a poor seal or a drain that empties slowly turns a safety upgrade into a daily frustration, and cold London mornings make a long drain wait miserable. The trade-off is plain. A specialist install costs more up front. In our experience that money buys a tighter door, faster drain, and someone who answers the phone in year two, which is where the value really shows.
One more London note. If your parent's mobility is changing quickly, or a second-floor bath is the only option, ask the installer whether a curbless shower or a stair lift would serve better before committing. A good advisor will tell you when a tub isn't the right call.
