Ditto on cutouts and body lift
Fender cutouts most cost effective and common way to go for larger tires. Not knowing UK or EU standards relating to sides tires sticking out of fender well you may need extended cut out fender flares. I've seen the use of lawn poly/plastic lawn edging to extend out over cutout fender wells to cover tires where regulations require tires to be covered.
A body lift are a great idea however there maybe issues at the radiator shroud and cooling fan clearance so radiator shroud modifications are required. The body lift would allow the same ride as now, stiffer springs may prevent full articulation of axles.
Anyway, good luck with your effort!
99 GMC SUB, 2500, 4x4, 6.5 TD (F) #H32 enhanced blk, Phaser timing set, B&D IC, 3" ATS exh, K&N w/prefilter, 4WD NVG 246, 4L80E kevlar Transgo off road/tow mods/B&M supercooler, 14 FF MagTec w/locker 3.42:1, 9.25" IFS frt/diff 3.42:1 w/ARB locker, AutoMeter Boost & pre-turbo pyro meter, 12,000 lb hydro winch, Warn classic bumper w/brushguard & diesel scoop, Max E-torq Stage 3, hi pop inj, oil bypass sys, on board air comp for front ARB locker & tire inflation, DynaView driving/auto-cornering lts, DZ nerfs, A/T 285/75/16 SilentArmor 3750 lb rated on 3750 lb rated Alcoa, 3 IP drivers 2 r spares.