At Tyres.co.uk, front options for the Vauxhall Lotus Carlton include the Goodyear Eagle F1 Asymmetric 6 and the Federal 595 Evo in 235/45 R17 97Y XL. At the rear the Federal 595 Evo is listed in 265/40 ZR17 96Y. Check the fitment on the vehicle to confirm the staggered front and rear sizes.
For details on the Vauxhall Lotus Carlton, the pressure sticker on the inside of the fuel filler flap, on the right rear side of the vehicle, contains the necessary information. The sticker will either detail front and rear different sizes of tyres or, at the minimum, the pressures.
It is not necessary to replace all four tyres on a Vauxhall Lotus Carlton. Since this vehicle is rear-wheel drive, there is no need to worry about matching rolling circumferences on both front and rear axles. As per UK tyre-safety policy, when replacing two tyres, they should be fitted to the rear axle.